Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
1999-07-08
2001-06-26
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S613000
Reexamination Certificate
active
06251765
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to semiconductor integrated circuits, and more particularly, to an apparatus and method for forming metal (e.g., solder) bumps onto a surface of a semiconductor integrated circuit, such as a spherical-shaped semiconductor device.
Conventional integrated circuit devices, or “chips,” are formed from a flat surface semiconductor wafer. The semiconductor wafer is first manufactured in a semiconductor material manufacturing facility and is then provided to a fabrication facility. At the latter facility, several layers are processed onto the semiconductor wafer surface. Once completed, the wafer is then cut into one or more chips and assembled into packages. Usually, electrical connections are made inside the packages from the input and output pads of the chip to the input and output pins or leads of the packages. Thereafter, the packages are secured to a circuit board or seated into reception sockets which can then be soldered to the circuit board. There are many different types of packages, including solid lead packages (e.g., PDIP, SOJ), and various solder bump packages (e.g., flip chip). For the solder bump-type packages, solder bumps make electrical connections directly between the chip and the circuit board or the reception socket.
In U.S. patent application Ser. No. 08/858,004 filed on May 16, 1997, a method and apparatus for manufacturing spherical-shaped semiconductor integrated circuit devices is disclosed. One way to connect the spherical shaped semiconductor devices to packages or circuit boards is to use multiple micro metal balls or stud bumps at certain areas of each spherical shaped semiconductor device. This can be an expensive process since not only do the stud bumps or micro metal balls have to be manufactured separately, additional steps must be taken to carefully connect them to predetermined locations of the spherical shaped semiconductor device.
What is needed is a system and method for effectively and economically forming solder bumps on a surface of a semiconductor integrated circuit, such as a spherical-shaped semiconductor device.
SUMMARY OF THE INVENTION
The present invention discloses a system and method for efficiently and economically forming solder bumps on the surface of a semiconductor integrated circuit, such as a spherical-shaped semiconductor device. Using solder bumps eliminates an expensive manufacturing process step for the device. Further, it also eliminates the need to plant stud bumps and micro balls carefully to certain locations on devices such as a spherical shaped semiconductor device.
In one of the embodiments, a batch of spherical shaped semiconductor devices can be held by a vacuum chuck and dipped into different molten metal compounds to form a plurality of solder bumps. A method is disclosed for aligning the spherical shaped semiconductor devices in such a way that the vacuum chuck can hold all of the devices with an appropriate orientation. The spherical shaped semiconductor devices are preprocessed to have certain metal electrode pads on them to induce the growth of the bumps when the devices are dipped in solder materials. In some embodiments, different solder materials having various melting points are utilized to support sequential applications of solder layers on the electrode pads. Among various factors that collectively control the characteristic of the solder bumps, viscosities of solder material and the size of the electrode pads are two important factors that significantly affect the end result of the dipping process. Once the solder bumps are grown on the spherical shaped semiconductor devices, the vacuum chuck can immediately transfer the devices to a tape-and-reel assembly for further transportation thereof. It can also be easily fed into a tube assembly which also protects the spherical shaped semiconductor device with the solder bumps during the shipping process.
As such, the present invention helps to mass produce solder bumps connected to semiconductor devices and arrange such processed devices in economical shipping assemblies. It can thereby effectively reduce the overall cost of manufacturing such semiconductor devices.
REFERENCES:
patent: 5143865 (1992-09-01), Hideshima et al.
patent: 5955776 (1999-09-01), Ishikawa
Fukano Atsuyuki
Takeda Nobuo
Ball Semiconductor Inc.
Gurley Lynne A.
Haynes and Boone LLP
Niebling John F.
LandOfFree
Manufacturing metal dip solder bumps for semiconductor devices does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Manufacturing metal dip solder bumps for semiconductor devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Manufacturing metal dip solder bumps for semiconductor devices will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2510461