Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2002-05-21
2003-08-26
Whitehead, Jr., Carl (Department: 2813)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S613000, C438S617000
Reexamination Certificate
active
06610590
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a wafer-level chip size package (WCSP).
The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2001-155148, filed May 24, 2001, which is herein incorporated by reference in its entirety for all purposes.
2. Description of the Related Art
The WCSP is one of semiconductor mold packages, a that has simple packaging. A plurality of pads are constructed for a plurality of semiconductor chips, are formed on a silicon substrate at the wafer-level. Then, bump electrodes for an assembly are formed, after wiring patterns connecting the pads are formed. Next, solder balls for packaging are formed on the bump electrodes. Finally, the wafer-level silicon substrate is divided into chip size pieces. At this time, between the pads, the wiring patterns and the bump electrodes are electrically connected by using solder balls, for instance. Similarly to other types of mold packages, such as a ball grid array (BGA) and a chip size package (CSP), manufacturing of the WCSP is performed as an assembly process.
Since such a WCSP is a commodity transacted at the wafer-level as well as the chip size level, both of the chip size and wafer levels are impressed with a commodity description or identification. Commonly, since the pads, the wiring patterns and the bump electrodes are formed on a device surface of the silicon substrate, an impression for the WCSP is performed on a back surface which is opposite from the device surface. A conventional impression method for the WCSP, method is stamp printing using a rubber-stamp. However, the stamp printing has a few disadvantages, for example wear of the stamp and changing of ink. Also, a laser impression that is to be applied to another mold package must be set up, a slowing the process and increasing cost.
At the back surface of a conventional WCSP, since no resist is applied after back-grinding of the WCSP, the silicon substrate is barely formed. When the laser impression is formed in such a WCSP, thermal energy of laser light is conducted at the device surface (a surface of integrated circuit), whereby aluminum wiring is damaged and bonding between aluminum pads and wiring patterns may be destroyed.
SUMMARY OF THE INVENTION
The present invention is therefore directed to providing a method of manufacturing a semiconductor device, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.
It is an objective of the invention to provide a semiconductor device and a method of manufacturing the same, whereby a laser impression is formed on, the semiconductor device without any negative effects on the device surface of the semiconductor wafer (chip) due to exothermic heat generated during formation of the laser impression.
To achieve the above noted and other objects, a semiconductor device and a method of manufacturing the same of the present invention includes forming a low thermal conductivity layer on the back surface of the semiconductor wafer (chip), and the laser impression is formed on the low thermal conductivity layer.
According to the present invention, the laser impression can be formed without damaging the device surface of the semiconductor wafer (chip).
The above and further objects and novel features of the invention will more fully appear from the following detailed description, appended claims and accompanying drawings.
REFERENCES:
patent: 6294840 (2001-09-01), McCormick
patent: 6495393 (2002-12-01), Blish et al.
Jr. Carl Whitehead
Nguyen Thanh
Oki Electric Industry Co. Ltd.
Volentine & Francos, PLLC
LandOfFree
Method of manufacturing a laser impression on a low thermal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing a laser impression on a low thermal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing a laser impression on a low thermal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3091297