Semiconductor device manufacturing: process – Having diamond semiconductor component
Reexamination Certificate
2002-07-05
2004-01-06
Whitehead, Jr., Carl (Department: 2813)
Semiconductor device manufacturing: process
Having diamond semiconductor component
C438S106000, 37
Reexamination Certificate
active
06673649
ABSTRACT:
TECHNICAL FIELD
The present invention is directed generally toward microelectronic device packages and methods for controlling the disposition and/or extent of non-conductive materials in such packages.
BACKGROUND
Existing microelectronic device packages typically include a microelectronic substrate or die attached to a support member, such as a printed circuit board. Bond pads or other terminals on the die are electrically connected to corresponding terminals on the support member, for example, with solder balls. The connection between the die and the support member can be encapsulated, for example, with a protective underfill material, to form a device package. The package can then be electrically connected to other microelectronic devices or circuits, for example, in a consumer or industrial electronic product such as a computer.
In one existing arrangement shown in
FIG. 1
, a package
10
can include a support member
20
that carries a microelectronic die
30
. Solder balls
50
provide an electrical connection between upwardly facing bond pads of the support member
20
and downwardly facing bond pads of the die
30
. Accordingly, a gap (partially filled by the solder balls) is initially formed between the support member
20
and the die
30
.
In one existing process, an underfill material
40
is initially disposed adjacent to two of the outer edges of the die
30
. The underfill material
40
flows into the gap between the die
30
and the support member
20
to provide a protective encapsulant around the solder balls
50
. The underfill material
40
can flow both directly into the gap (as indicated by arrows A) and around the outer edges of the die
30
(as indicated by arrows B).
One characteristic the process described above with reference to
FIG. 1
is that in some cases, the underfill material
40
can flow more quickly around the die
30
(arrows B) than directly into the gap beneath the die
30
(arrows A). Accordingly, the underfill material
40
can trap air or other gases in the gap. A drawback with this arrangement is that the gases within the gap may expand when the temperature of the package
1
.
0
is elevated, causing the electrical connections provided by the solder balls
50
between the die
30
and the support member
20
to fail.
One existing approach for addressing the foregoing drawback is to control the viscosity of the underfill material
40
so that it preferentially wicks more quickly through the gap than around the periphery of the die
30
. For example, the viscosity can be controlled by controlling the temperature at which the underfill process is conducted, or the concentration of particulates in the underfill material
40
. Alternatively, the surface characteristics of the die
30
and/or the support member
20
can be selected to produce a faster underfill flow rate through the gap than around the periphery of the die
30
. Although the foregoing methods can produce satisfactory results, it may in some cases be difficult and/or expensive to accurately control the aforementioned variables. Furthermore, the underfill material
40
typically provides a permanent bond between the die
30
and the support member
20
, making it difficult if not impossible to replace a defective die
30
without destroying the entire package
10
.
SUMMARY
The present invention is directed toward microelectronic packages and methods for forming such packages. A method in accordance with one aspect of the invention includes positioning a microelectronic substrate proximate to a support member, with the microelectronic substrate having a first surface, a second surface facing opposite from the first surface, and a plurality of first connection sites at least proximate to the first surface. The support member can have a plurality of second and third connection sites. The method can further include connecting the microelectronic substrate to the support member by attaching a plurality of electrically conductive couplers between the plurality of first connection sites and the second connection sites, with neighboring conducted couplers being spaced apart to define at least one fluid flow channel, and with the support member and the microelectronic substrate forming a package. The package can then be provided for electrical coupling to other electrical structures via the third connection sites, with the at least one fluid flow channel accessible to a region external to the package.
In another aspect of the invention, flowable, electrically conductive couplers can be disposed at the first connection sites, and a generally non-conductive material can be disposed between the conductive couplers. A gap dimension can be selected based on a target underfill flow rate, and at least a portion of the generally non-conductive material can be removed to form a gap having the selected gap dimension and being positioned between neighboring conductive couplers. The microelectronic substrate and the support member can be connected by attaching the conductive couplers to the second bond sites of the support member, and an underfill material can be flowed into the gap at at least approximately the target underfill material flow rate.
A method in accordance with another aspect of the invention includes providing a first microelectronic substrate having first connection sites carrying first flowable, electrically conductive couplers that define a first plane. A first generally non-conductive material is applied to the first conductive couplers and to the first microelectronic substrate, and at least some of the first generally non-conductive material is removed to recess the first generally non-conductive material from the first plane by a first recess distance. The method can further include providing a second microelectronic substrate having second flowable, electrically conductive couplers defining a second plane spaced apart from the second microelectronic substrate by a second distance different than the first distance. A second generally non-conductive material is applied to the second conductive couplers, and at least some of the second generally non-conductive material is removed from between the second conductive couplers to recess the second generally non-conductive material from the second plane by a second recess distance that is at least approximately the same as the first recess distance.
A method in accordance with still another aspect of the invention includes connecting the microelectronic substrate to the support member by attaching the conductive couplers and disposing at least one generally non-conductive material adjacent to the conductive couplers, with the at least one generally non-conductive material being spaced apart from the support member. In another aspect of the invention, the at least one generally non-conductive material can be a first generally non-conductive material, and the method can further include disposing a second generally non-conductive material adjacent to the support member and the conductive couplers, with the second generally non-conductive material being spaced apart from the first generally non-conductive material.
A method in accordance with yet another aspect of the invention includes providing a first. generally non-conductive material between flowable conductive couplers of a microelectronic substrate, with the first generally non-conductive material being recessed to define a flow channel having an inner region and an outer region disposed outwardly from the inner region. A second generally non-conductive material can be disposed on the support member to form a layer having a first region and a second region disposed outwardly from the first region, with the first region having a greater thickness than the second region. The inner region of the flow channel is then engaged with the first region of the second generally non-conductive material, while the second generally non-conductive material is at least partially flowable, and the microelectronic substrate and the support member are moved toward each other while forcing gas wi
Farnworth Warren
Hiatt William Mark
Jr. Carl Whitehead
Micro)n Technology, Inc.
Perkins Coie LLP
Schillinger Laura
LandOfFree
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