Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
1995-12-21
2002-09-10
Graybill, David E. (Department: 2827)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S613000, C438S614000, C438S615000, C438S616000, C228S180220
Reexamination Certificate
active
06448169
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to an apparatus and method for use in manufacturing a semiconductor device including an input-output (IO) face having a plurality of IO lands. The semiconductor device is situated in an operating position with a mold for depositing solder ball connection structures to the IO lands for implementing controlled collapse chip connection (C
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) IO connection structures. Such solder ball C
4
connection structures are useful for such semiconductor devices as single-chip or multi-chip module packages. In particular, the apparatus of the present invention is directed to a fixture for use in selectively positioning a semiconductor device and a depositor in a manufacturing process, and for separating the semiconductor device and depositor to a separation distance while the semiconductor device and depositor are subjected to appropriate ambient conditions for effecting reflow of the solder material in the depositor. The method of the present invention includes the steps of separating the semiconductor device and the depositor to a separation distance after effecting initial reflow of solder to form interim solder balls, and effecting continued reflow (or a renewed reflow) of the interim solder balls to final solder balls free of imperfections impressed in the interim solder balls by contact with cavities in the depositor.
When using a depositor having a plurality of cavities containing solder material for wettingly applying the solder material to the IO lands of a semiconductor device, there is a need to ensure that no more than a predetermined distance separates the cavity bottom from the IO lands. A predetermined amount of solder is contained within each depositor cavity to produce the desired amount of solder on the IO land. If the distance between the cavity bottom and the IO land is too great, then the solder will not reach the IO land when the semiconductor device and the depositor are in the operating position and no solder deposition will occur. However, when there is an appropriate distance between the IO land and the solder material within the cavity (i.e., the cavity depth is appropriate for the desired amount of solder to be deposited on the IO land), then there is continued contact between the deposited solder and the depositor after solder deposition has occurred. Thus, in such situations, after reflow has formed the solder ball there is an impression of the depositor left on the solder structure. This impression precludes the solder structure's achieving a true solder ball configuration. Such untrue shape contributes to unpredictability in solder ball connection in C
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connection operations between the semiconductor device and other components.
What is needed is an apparatus and a method to ensure that solder depositions are reliably and repeatably effected when a depositor is used for depositing solder to a semiconductor device. There must be true solder ball depositions on the semiconductor device IO lands.
SUMMARY OF THE INVENTION
The invention is an apparatus for use in manufacturing a semiconductor device. The semiconductor device includes an input-output (IO) face having a plurality of IO lands, and is situated in an operating position in substantially abutting relation with a depositor. The apparatus includes a first holding member which holds the depositor in a first position; a second holding member which holds the semiconductor device in the operating position. The depositor and the semiconductor device cooperate in the operating position to deposit solder ball connection structures to the IO lands. The apparatus further includes a separating member for moving at least one of the depositor and the semiconductor device from the operating position to an interim orientation. The interim orientation establishes a separation distance intermediate the depositor and the semiconductor device appropriate to disengage the solder ball connecting structures from the depositor.
In the preferred embodiment of the invention, the separating means includes a bias means which urges the depositor and the semiconductor device apart. The bias means preferably has a thermal coefficient of expansion (TCE) appropriate to expand the bias means a predetermined distance when subjected to temperatures appropriate for solder reflow. The separating means further includes a separator actuator. The bias means is situated at a first locus intermediate the depositor and the semiconductor device; the separator actuator is situated at a second locus intermediate the depositor and the semiconductor device. The bias means and the separator actuator cooperate in response to application of appropriate heat to expand the bias means to displace the semiconductor device and the depositor. Separation of the semiconductor device and the depositor occurs with the depositor and the semiconductor device in substantially parallel planes. A preferred structure for the separator actuator is a wedge structure which is biasedly urged intermediate the semiconductor device and the depositor. Another structure for the separator actuator is a lever structure which is biasedly urged intermediate the semiconductor device and the depositor.
In its most preferred embodiment, the invention is a fixture for use in selectively positioning a semiconductor device and a depositor in a manufacturing process. The semiconductor device includes an input-output (IO) face having a plurality of IO lands. The semiconductor device and the depositor are positioned in an operating position in substantially abutting relation with the IO face adjacent the depositor and the plurality of IO lands substantially in register with a plurality of cavities in the depositor. The fixture includes a base member which holds the depositor in a first position; an urging member which urges the semiconductor device against the base member in the operating position; and a separating member which is configured for selective actuation while the semiconductor device and the depositor are in the operating position and are exposed to appropriate ambient conditions to effect reflow of solder material in the plurality of cavities. The actuation moves the semiconductor device and the depositor to an interim orientation which establishes a separation distance intermediate the depositor and the semiconductor device appropriate to disengage the solder material from the depositor.
It is, therefore, an object of the present invention to provide an apparatus for use in manufacturing a semiconductor device with a depositor for depositing solder ball connection structures to input-output (IO) lands of the semiconductor device which reliably and repeatably ensures the attainment of true solder ball configured connection structures.
It is also an object of the present invention to provide a method for reliably and repeatably attaining true solder ball configured connection structures when using a depositor for depositing solder ball connection structures to IO lands of a semiconductor device.
Further objects and features of the present invention will be apparent from the following specification and claims when considered in connection with the accompanying drawings illustrating the preferred embodiment of the invention.
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Brearley William
Economikos Laertis
Findeis Paul F.
Kelly Kimberley A.
Leenstra Bouwe W.
Graybill David E.
International Business Machines - Corporation
Pepper Margaret A.
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