Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2001-01-04
2004-04-06
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S113000, C438S114000, C438S127000, C438S460000
Reexamination Certificate
active
06716665
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of making a semiconductor chip out of a wafer as a bulk of semiconductor chips, and to a method of mounting a semiconductor chip onto a printed circuit board or substrate.
2. Description of the Prior Art
A semiconductor chip such as an integrated circuit (IC) is in general cut out of a silicon wafer. The cut out semiconductor chip is then mounted onto a printed circuit board. When the semiconductor chip is mounted in this manner, input/output bumps on the semiconductor chip is received on the surface of a substrate of the printed circuit board. The input/output bumps serve to establish an electric connection between the semiconductor chip and the printed circuit board.
An underfill material is filled in a space between the semiconductor chip and the substrate of the printed circuit board. The underfill material serves not only to prevent any deterioration such as corrosion of the input/output bumps but also to reinforce the bonding between the semiconductor chip and the substrate of the printed circuit board.
In general, a dispenser is employed to supply the underfill material. The dispenser is designed to discharge the liquid of the underfill material for the individual semiconductor chips one after another. It takes a longer time to supply the underfill material to all of the semiconductor chips.
In addition, the input/output bumps are in general formed on the upward surface of the silicon wafer. The individual semiconductor chip cut out of the silicon wafer should be reversed before the semiconductor chip is actually mounted on the substrate of the printed circuit board. It also takes a longer time to reverse each of the semiconductor chips cut out of the wafer.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a method of mounting a semiconductor chip onto a printed circuit board in a shortened working time.
According to the present invention, there is provided a method of supplying an underfill material for a semiconductor chip, comprising: locating a wafer which receives a conductive bump on an upward front side; and transferring an underfill material sheet adhered to a surface of a thin film member onto the upward front side of the wafer.
The underfill material can be supplied commonly to a plurality of semiconductor chips included in the wafer in the method of supplying. Accordingly, the working time can greatly be reduced as compared with the case where the underfill material is supplied separately to the individual semiconductor chips. In particular, if the supply of the underfill material can be completed before the semiconductor chip is mounted on a printed circuit board or substrate in this manner, the method of mounting the semiconductor chip onto a printed circuit board or substrate is supposed to be facilitated.
The method of supplying may further comprise: urging the underfill material sheet onto the upward front side of the wafer after softening the underfill material sheet when transferring the underfill material sheet onto the wafer; and peeling the thin film member from the underfill material sheet after hardening the underfill material sheet. The transfer of the underfill sheet in this manner may be achieved prior to or after cut-out of the individual semiconductor chips.
According to a second aspect of the present invention, there is provided a method of mounting a semiconductor chip onto a printed circuit board or substrate, comprising reversing a wafer as a bulk of semiconductor chips prior to pickup of an individual semiconductor chip.
The method of mounting allows the semiconductor chips to be reversed in the block. Accordingly, the working time can greatly be reduced as compared with the case where the individual semiconductor chips are separately reversed.
According to a third aspect of the present invention, there is provided a method of mounting a semiconductor chip onto a printed circuit board or substrate, comprising: forming a conductive bump on an upward front side of a wafer; dicing the wafer on a first support member so as to cut out individual semiconductor chips; superposing a second support member over the first support member so as to hold the semiconductor chips between the first and second support members; reversing the first support member along with the second support member holding the semiconductor chips therebetween; picking up the individual semiconductor chips after removing the first support member.
The method of mounting allows the semiconductor chips, held between the first and second support members, to be reversed in the block. Accordingly, the working time can greatly be reduced as compared with the case where the individual semiconductor chips are separately reversed.
According to a fourth aspect of the present invention, there is provided a method of making a semiconductor chip, comprising: forming a conductive bump on an upward front side of a wafer; reversing the wafer; and forming a resin lamination on a backside of the wafer.
The resin lamination can be formed on the backsides of the individual semiconductor chips cut out of the wafer in the method of making. The resin lamination is allowed to hold tiny fragments, fractured out of the semiconductor chip, on the semiconductor chip. The resin lamination thus prevents a scatter or drop of the tiny fragments. The resin lamination serves to reliably suppress generation of dust resulting from the semiconductor chip to the utmost.
In providing the resin lamination, the method of making may further comprise transferring a resin sheet, adhered to a surface of a thin film member, to the backside of the wafer. This process enables a common supply of the resin lamination to a plurality of semiconductor chips included in the wafer. Accordingly, the working time can greatly be reduced as compared with the case where formation of the resin lamination is conducted separately for the individual semiconductor chips. In particular, if the supply of the resin lamination can be completed before the semiconductor chip is mounted on a printed circuit board or substrate in this manner, the method of mounting the semiconductor chip onto a printed circuit board or substrate is supposed to be facilitated.
According to a fifth aspect of the present invention, there is provided a method of making a semiconductor chip, comprising: reversing a wafer receiving a conductive bump on an upward front side; and dicing the wafer from a backside of the wafer.
When the dicing process is effected on the wafer, the individual semiconductor chips can be cut out of the wafer. The cut out semiconductor chip is then picked up, so that it can be mounted on a printed circuit board or substrate. It is not necessary to reverse the individual semiconductor chips after the dicing process in mounting the semiconductor chip onto a printed circuit board or substrate. Accordingly, the subsequent method of mounting can thus greatly be facilitated. The working time can further be shortened.
The wafer may be subjected to irradiation of an electromagnetic wave. Any metallic lamination and/or conductive bumps are in general supposed to block the transmission of the electromagnetic wave. The electromagnetic wave passing or penetrating through the wafer is allowed to reveal the position and shape of the metallic lamination and/or conductive bumps. The thus revealed positions for the metallic lamination and/or conductive bumps in this manner enable a precise and reliable determination of the cutting position in a facilitated manner without directly observing the metallic lamination and/or conductive bumps.
The method of making may further comprise: forming a nick along a contour of the semiconductor chip on the backside of the wafer. If an evaporated resin lamination is formed within the nick, a broader coverage of the evaporated resin lamination can be obtained over the surface of the resulting semiconductor chip as compared with the case where the individual semiconductor chips are simply cut
Baba Shunji
Kainuma Norio
Kira Hidehiko
Kobae Kenji
Kobayashi Hiroshi
Fujitsu Limited
Niebling John F.
Roman Angel
Staas & Halsey , LLP
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