Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Encapsulating
Reexamination Certificate
2001-03-13
2003-03-25
Picardàt, Kevin M. (Department: 2822)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Encapsulating
C438S112000, C438S124000, C438S126000
Reexamination Certificate
active
06537859
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for baking a semiconductor device that has a semiconductor element and a resin encapsulated package.
Semiconductor devices such as a transistor, an integrated circuit (IC) and a large scale integrated circuit (LSI) are each encapsulated in a ceramic package, a plastic package or the like. The plastic package is going mainstream, except for particular specifications, since it is especially excellent in terms of cost and productivity.
FIG. 2
is a schematic sectional view of a semiconductor device that has a plastic package of the thin small outline package (TSOP) type or the like. This semiconductor device
100
shown in
FIG. 2
has assembly processes as follows.
First of all, a die bonding paste containing an organic solvent is coated on a frame
101
made of alloy, and a semiconductor chip
102
bis die-bonded onto the frame
101
.
Next, the semiconductor chip
102
and the frame
101
are subjected to a heating process in an N
2
atmosphere by means of an oven and thereafter to a wire bonding process to connect the semiconductor chip
102
with lead terminals
103
and
103
by way of Au wires
106
and
106
.
Next, before performing resin encapsulation, a polyimide based resin (PIQ) film
104
is formed on a surface of the frame
101
opposite to the semiconductor chip
102
in order to secure adhesion of the frame
101
to a plastic package
105
. Thereafter, the PIQ film
104
is subjected to a heating process for hardening it.
Next, resin is molded into the package
105
of the TSOP type by a molding press after completing the heating process of the PIQ film
104
, and then the package
105
of the TSOP type is subjected to a heating process in a N
2
atmosphere.
Next, the lead terminals
103
and
103
are formed, subjected to a plating process, and followed by a baking process.
In a conventional baking method of a semiconductor device, moisture absorbed in the plastic package
105
and organic components contained in the plastic package
105
are removed by subjecting the semiconductor device
100
to the baking process at a temperature 150° C. for one hour in a N
2
atmosphere at the atmospheric pressure.
However, the aforementioned semiconductor device baking method is not able to sufficiently remove the organic components contained in the plastic package
105
. Consequently, if a reflow process is performed at a temperature of e.g. 230° C. for three minutes to connect the semiconductor device
100
to a circuit substrate, there occurs a problem that a blister
105
a
shown in
FIG. 3
or cracks are generated in the plastic package
105
.
SUMMARY OF THE INVENTION
Accordingly, the present invention has an object of providing a semiconductor device baking method capable of preventing deformation such as blisters and cracks of a plastic package.
In order to achieve the aforementioned object, the present invention provides a semiconductor device baking method for baking a semiconductor device that has a semiconductor element and a resin encapsulated package, comprising the steps of: encapsulating the semiconductor element with resin into the resin encapsulated package; and baking the resin encapsulated package in a reduced-pressure atmosphere.
According to the present invention, it has been found that moisture and organic components inside the resin encapsulated package are easily discharged out of the resin encapsulated package by baking the resin encapsulated package in the reduced-pressure atmosphere. As a result, the moisture and the organic components inside the resin encapsulated package are sufficiently reduced, so that the resin encapsulated package can be prevented from deformation such as blisters and cracks in, for example, the reflow process after the baking process.
In one embodiment of the present invention, the reduced-pressure atmosphere is an atmosphere having a vacuum degree of 10
−6
torr or less.
According to the above embodiment, deformation such as blisters and cracks in the resin encapsulated package can more reliably be prevented by setting the reduced-pressure atmosphere to 10
−6
torr or less.
If the reduced-pressure atmosphere is greater than the value of 10
−6
torr, the moisture and the organic components inside the resin encapsulated package are insufficiently removed.
In one embodiment of the present invention, the resin encapsulated package is heated within a temperature range of 165° C. to 175° C. in the step of baking the resin encapsulated package.
According to the above embodiment, deformation such as blisters and cracks in the resin encapsulated package can more reliably be prevented by baking the resin encapsulated package within the temperature range of 165° C. to 175° C.
If the baking is performed at a temperature lower than 165° C., the moisture and the organic components inside the resin encapsulated package are insufficiently removed.
If the baking process temperature exceeds 175° C., the resin encapsulated package suffers heat damages.
In one embodiment of the present invention, the resin encapsulated package is heated for 6 hours or more in the step of baking the resin encapsulated package.
According to the above embodiment of the present invention, the deformation such as blisters and cracks in the resin encapsulated package can more reliably be prevented by heating the resin encapsulated package for 6 hours or more.
If the heating time of the resin encapsulated package is less than 6 hours, the moisture and the organic components inside the resin encapsulated package are insufficiently removed.
In one embodiment of the present invention, the resin encapsulated package belongs to a TSOP type.
According to the above embodiment of the present invention, deformation such as blisters and cracks in the resin encapsulated package can effectively be prevented since the resin encapsulated package belongs to the TSOP type.
REFERENCES:
patent: 4346449 (1982-08-01), Ovshinsky et al.
patent: 5825549 (1998-10-01), Kawamata et al.
patent: 6072243 (2000-06-01), Nakanishi
patent: 6211277 (2001-04-01), Kawata et al.
patent: 6214904 (2001-04-01), Tanaka et al.
patent: 6297543 (2001-10-01), Hong et al.
Nixon & Vanderhye P.C.
Picardát Kevin M.
Sharp Kabushiki Kaisha
LandOfFree
Semiconductor device baking method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device baking method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device baking method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3001256