Electric heating – Metal heating – By arc
Reexamination Certificate
2001-01-17
2002-09-24
Heinrich, Samuel M. (Department: 1725)
Electric heating
Metal heating
By arc
Reexamination Certificate
active
06455805
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to cutting circuit components on a microprocessor chip using laser trimming principles.
BACKGROUND OF THE INVENTION
A laser trimming handler is used to convey what are to become microprocessor chips across the path of a laser, which cuts predetermined circuit components into the chips. Several chips can be loaded onto a tray, with the tray then being placed at an input loading station and conveyed through the laser cutting chamber. The tray is extracted and unloaded at an output station.
It is to be appreciated that as microprocessor chips are made with ever-smaller circuit components, the above-described laser cutting process must make ever-finer cuts. The present invention has made the critical observation that the trays in which the microprocessor chips are borne through the cutting chamber are frequently reused, and that over the course of their lifetime can become bent and warped. The deformation of the trays is not noticeable to the human eye and consequently can remain undetected. Unfortunately, even a minute deformation of a tray can alter the cutting depth of the laser sufficiently to cause improper component formation. Accordingly, the present invention has provided the below-disclosed solutions to one or more of the above-noted problems.
BRIEF SUMMARY OF THE INVENTION
A device for promoting precise laser cuts in a laser trimming apparatus is disclosed. The laser trimming apparatus can include a conveyor system that moves trays into and out of a laser cutting chamber, with each tray holding plural semiconductor devices. The device of the present invention includes a rigid hard plate that preferably is made of steel and that is formed with at least one opening through which laser light can be directed. A lift system is engaged with the plate for moving the plate between a raised position, wherein the plate is distanced from a tray such that the tray can be moved beneath the plate, and a lowered position, wherein the plate contacts the tray to flatten the tray. The preferred plate is located within the cutting chamber.
In a preferred embodiment, at least one bottom edge of the plate is formed with a chamfer for aligning the plate with the tray. More preferably, the bottom edge includes two chamfers and a distance is defined between the chamfers. The distance is marginally larger than a length of an edge of the tray.
In another aspect, a method for undertaking a laser cut of at least one semiconductor device includes disposing the semiconductor device on a tray, and conveying the tray into a cutting chamber of a laser trimming apparatus. The method also includes lowering a plate onto the tray to flatten the tray. The plate defines at least one opening. Accordingly, a laser can be directed through the opening onto the semiconductor device to cut a component into the device. Then, the tray is conveyed out of the cutting chamber.
In still another aspect, an assembly for laser trimming includes a tray configured to hold semiconductor devices, and a laser cutting chamber is also included. A conveyor system conveys the tray into and out of the cutting chamber. A lift system selectively presses a plate against the tray to flatten the tray and thereby facilitate precise cutting.
Other features of the present invention are disclosed or apparent in the section entitled DETAILED DESCRIPTION OF THE INVENTION.
REFERENCES:
patent: 4328410 (1982-05-01), Slivinsky et al.
patent: 5099101 (1992-03-01), Millerick et al.
patent: 5504301 (1996-04-01), Eveland
patent: 5883357 (1999-03-01), Newman et al.
patent: 6040094 (2000-03-01), Otsuka et al.
patent: 6043453 (2000-03-01), Arai
patent: 6172330 (2001-01-01), Yamamoto et al.
patent: 9207313 (1997-08-01), None
patent: 11314189 (1999-11-01), None
patent: 2000288753 (2000-10-01), None
Boon Ronnie Lee Hock
Boon Thomas Wong Han
Chuan Koh Hock
Min Simon Cha Ser
Advanced Micro Devices , Inc.
Heinrich Samuel M.
LaRiveiere, Grubman & Payne, LLP
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