Semiconductor device manufacturing: process – Semiconductor substrate dicing
Reexamination Certificate
1999-07-07
2001-08-14
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Semiconductor substrate dicing
C438S068000, C438S460000
Reexamination Certificate
active
06274458
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to devices for cleaving semiconductor wafers, laser bars, and other products and workpieces. The present invention also relates to methods and systems for cleaving semiconductor devices and other products.
It is known to form laser diodes, photodetectors and other products from semiconductor wafers. During the fabrication of such products, the wafers may be separated or cleaved into laser bars. The resulting bars may be further cleaved into discrete semiconductor chips, if desired. Thus, a known method of forming semiconductor products involves scribing or scoring a semiconductor wafer, followed by cleaving the wafer along the scribed or scored lines.
U.S. Pat. No. 5,171,717 (Broom et al.) describes a method in which a semiconductor wafer is scribed and then placed between two transport bands. The transport bands are guided around a curved surface having a large radius. The surface applies a bending moment to the scribe lines to cleave the wafer. Similarly, U.S. Pat. No. 5,719,077 (Chakrabarti et al.) describes an apparatus that holds a semiconductor workpiece between a fixed jaw and a rotatable jaw. The rotatable jaw rotates to cleave the semiconductor workpiece.
The use of mechanically applied pressure to cleave laser bars and other brittle or fragile products may result in uneven or ragged cleaved edges. In particular, mechanical pressure on the laser bars may cause cracking, splitting, breaking or other damage. If a semiconductor product with an uneven cleaved surface is incorporated into an optical device, such as a laser, an insufficient light output or complete failure of the device may occur.
SUMMARY OF THE INVENTION
The present invention relates to a device for cleaving semiconductor products. The device includes an inlet for receiving pressurized gas, an adjustable slot for directing the gas toward the semiconductor products, and a movable flow control member for directing the gas toward the slot.
According to one aspect of the invention, the flow control member is located within a housing that also defines the inlet and the adjustable slot. A cover may be located on the front of the housing. The cover may have a lower edge that forms one side of the slot. The other side of the slot may be formed by the movable flow control member. Thus, the cleave device of the present invention may have an uncomplicated, compact construction.
The present invention also relates to an apparatus for cleaving brittle products. The apparatus may include a flexible structure for transporting the products to a cleaving position, and a device for flowing pressurized gas onto the flexible structure to bend the products at the cleaving position. The gas flow device may have an adjustable slot formed by a movable flow control member. In a preferred embodiment of the invention, the gas flow device forms a sheet of pressurized gas that may be used to cleave one or more brittle products along preformed scribe or score lines at the cleaving position.
According to another aspect of the invention, the brittle products, which may be wafers or laser bars, are transported within opposed flexible sheets. The sheets may be used to locate the products over a ledge where they are bent to cause cleaving along crystal planes initiated at scribe or score lines.
The present invention also relates to a method of handling semiconductor products. The method may include the following steps: locating the products in a flexible structure; moving the flexible structure to a cleaving position; and flowing pressurized gas through an adjustable slot to bend the flexible structure at the cleaving position. In a preferred embodiment of the invention, the width of the slot is adjusted by moving a flow control member within a housing. The device may be arranged such that adjustment of the slot causes corresponding movement of an integral surface within the housing, such that gas flows smoothly through the housing regardless of the position of the flow control member.
In a preferred embodiment of the invention, pressurized gas is redirected from one or more discrete sources and formed into a uniform sheet. This way, uniform bending forces may applied across the full width or widths of the scribed semiconductor product(s). The pressure and cross sectional dimensions of the gas flow through the slot may be precisely controlled, if desired.
According to a preferred embodiment of the invention, an apparatus is arranged to apply gentle, uniform pressures to cleave laser bars. The invention may be used to increase production yield by reducing the number of integrated circuits formed with defects due to cracking or splitting of the material.
These and other features and advantages will become apparent from the following detailed description of preferred embodiments of the present invention.
REFERENCES:
patent: 5154333 (1992-10-01), Bauer et al.
patent: 5171717 (1992-12-01), Broom et al.
patent: 5719077 (1998-02-01), Chakrabarti et al.
patent: 5968382 (1999-10-01), Matsumoto et al.
patent: 6102267 (2000-08-01), Freund et al.
Freund Joseph Michael
Przybylek George John
Romero Dennis Mark
Agere Systems Optoelectronics Guardian Corp.
Dickstein , Shapiro, Morin & Oshinsky, LLP
Le Dung A
Nelms David
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