Encapsulation methods for semiconductive die packages

Details Encapsulation methods for semiconductive die packages Encapsulation methods for semiconductive die packages

1999-07-26

2002-04-30

Bowers, Charles (Department: 2829)

Semiconductor device manufacturing: process

Making device or circuit responsive to nonelectrical signal

Responsive to electromagnetic radiation

C264S494000, C430S311000, C430S321000, C438S004000, C438S026000, C438S064000

Reexamination Certificate

active

06379991

ABSTRACT:

TECHNICAL FIELD
The invention pertains to methods of forming encapsulant over semiconductor dies, such as, for example, methods of forming die packages.
BACKGROUND OF THE INVENTION
A prior art method of forming a die package is described with reference to
FIGS. 1-7
. Referring first to
FIG. 1
, such illustrates a fragment of an assembly
10
comprising an insulative material substrate
12
. Insulative substrate
12
comprises a top surface
13
and slits
18
extending therethrough. Circuitry
16
is formed on top surface
13
. Circuitry
16
and slits
18
form repeating patterns across top surface
13
. The repeating patterns define separate units
19
,
21
and
23
, each of which ultimately forms a separate die package.
Referring to
FIGS. 2-4
, an enlarged segment of substrate
12
, corresponding to unit
21
, is shown in three different views.
FIG. 2
is a top view similar to the view of
FIG. 1
,
FIG. 3
is an end view, and
FIG. 4
is a cross-sectional top view along the line
4
—
4
of FIG.
3
.
Substrate
12
comprises a bottom surface
15
. A semiconductive-material-comprising die (or chip)
14
is adhered to bottom surface
15
via a pair of adhesive strips
20
. Strips
20
can comprise, for example, tape having a pair of opposing surfaces
22
and
24
, with adhesive being provided on both of such opposing surfaces. Adhesive strips
20
space die
14
from insulative substrate
12
, and accordingly form a gap
26
between die
14
and insulative material
12
. Strips
20
can accordingly be considered spacers. Gap
26
is in the form of a channel that extends from one end of strips
20
to another end of strips
20
. Preferably, strips
20
comprise insulative material such that strips
20
do not form an electrical connection between die
14
and conductive circuitry associated with substrate
12
.
Wire bonds
28
(only some of which are labeled in
FIG. 2
) extend from circuitry
16
, through slit
18
and gap
26
, to electrically connect circuitry
16
to bonding pads
25
(only some of which are labeled in
FIG. 2
) associated with die
14
, and to accordingly electrically connect circuitry
16
with circuitry (not shown) comprised by die
14
. (The wire bonds and bonding pads are not shown in
FIGS. 3 and 4
for purposes of clarity in the illustrations.)
After wire bonds
28
are formed, an encapsulant is provided over wire bonds
28
to protect such wire bonds. A method of providing the encapsulant is described with reference to
FIGS. 5 and 6
. Referring to
FIG. 5
, the die assembly of
FIG. 4
is shown at an initial stage of the encapsulant-forming methodology. Specifically, dams
27
and
29
are formed at ends of gap
26
. Such dams can be formed by, for example, dispensing and curing liquid encapsulant at the die sides.
Referring to
FIG. 6
, an encapsulant
30
is provided through slit
18
after dams
27
and
29
(
FIG. 5
) are formed. Specifically, an injector
31
is provided over slit
18
and utilized to inject encapsulant
30
through slit
18
and into gap
26
to substantially fill gap
26
and slit
18
. By “substantially fill” it is meant that the encapsulant fills more than half of the combined space of gap
26
and slit
18
. In particular applications, the encapsulant can completely fill gap
26
and slit
18
. The encapsulant utilized is generally a heat curable epoxy. Accordingly, the encapsulant is provided within gap
26
as a liquid, and subsequently subjected to heat to cure the encapsulant into a more solid form.
After encapsulant
30
is provided and cured, circuitry
16
and die
14
can be subjected to additional package-forming steps. For instance,
FIG. 7
illustrates a portion of substrate
12
(specifically, a portion comprising units
19
and
21
) at a step subsequent to curing of encapsulant
30
. Conductive balls
31
(only some of which are labeled) have been formed over portions of circuitry
16
to form a ball grid array which can be subsequently utilized to form a plurality of interconnects from circuitry
16
to other circuitry (not shown).
FIG. 7
further illustrates that substrate
12
can be subjected to a singulation process to separate units
19
and
21
from one another, and thus form individual die packages from units
19
and
21
.
It would be desirable to develop alternative methods of forming semiconductive die packages. It would be particularly desirable to develop alternative methods of providing encapsulant over wire bonds associated with semiconductive die packages.
SUMMARY OF THE INVENTION
In one aspect, the invention encompasses a semiconductor processing method. An insulative substrate is provided. Such substrate has a pair of opposing surfaces and an opening extending therethrough. The opening extends from one of the opposing surfaces to another of the opposing surfaces. A semiconductor-material-comprising die is provided adjacent to said one of the opposing surfaces of the insulative substrate, and the die has an edge. A gap is between the die and insulative substrate, and exposed through the opening. A liquid radiation-curable material is flowed through the opening and into the gap. Radiation is directed from beside the die to cure at least a portion of the radiation-curable material within the gap and thus form a dam which impedes non-cured radiation-curable material from flowing beyond the edge.
In another aspect, the invention encompasses a method of forming a die package. An insulative substrate is provided, and such substrate has an underside and an opposing topside. Circuitry is over the topside of the insulative substrate, and a slit extends through the insulative substrate. A semiconductive-material-comprising die is provided beneath the underside of the insulative substrate, and has a surface exposed through the slit in the insulative substrate. The die has an edge. There is a gap between the die and the underside of the insulative substrate. A radiation-curable material is injected through this slit and into the gap. Radiation is directed from over the edge to the gap to cure at least a portion of the radiation-curable material within the gap and thus form a dam which impedes non-cured radiation-curable material from flowing beyond the edge.


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