Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
1998-10-26
2001-02-06
Davis, Jenna (Department: 1771)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S171000, C528S172000, C528S176000, C528S184000, C528S185000, C528S188000, C528S352000, C528S353000, C528S360000, C528S363000, C528S367000
Reexamination Certificate
active
06184337
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to adhesive tapes for electronic parts to be used for adhering between parts around leadframes making up a semiconductor device, e.g., lead pins, semiconductor chip mounted substrates, heat spreader, semiconductors themselves.
2) Description of the Related Art
Conventionally, adhesive tapes for fixing a leadframe, TAB tapes, etc., are used as adhesive tapes for use in the interior of resin-molded type semiconductor devices. For example, the adhesive tapes for fixing a leadframe have been used to fix lead pins of the leadframe in order to enhance the efficiency for producing the leadframe itself and the whole semiconductor assembly stages. In general, a leadframe manufacturer tapes a leadframe, and brings it to a semiconductor manufacturer, at which a semiconductor chip is mounted thereon followed by molding the leadframe with a resin. For this reason, it has been required for the adhesive tapes for fixing the leadframe not only to possess general reliability in a level required for semiconductor and enough processability at the time of taping, but also to possess sufficient adhesive strength immediately after taping and heat resistance enough for withstanding thermal process at the stages of assembling semiconductor devices. Conventionally, the adhesive tapes for use in such an application include adhesive tapes applying on a support film of a polyimide film, etc., an adhesive comprising polyacrylonitrile, polyacrylate or a synthetic rubber resin such as acrylonitrile-butadiene copolymer solely, or modified with any other resin or blended with any other resin to come into a B-stage.
In recent years, resin-molded type semiconductor devices as shown in
FIGS. 1
to
3
have been developed or produced. In
FIG. 1
, the device has a construction in which lead pins
3
and plane
2
are connected by means of an adhesive layer
6
, a semiconductor chip
1
is mounted on the plane
2
, and together with bonding wires
4
between the semiconductor chip
1
and the lead pins
3
, they are molded with a resin
5
. In
FIG. 2
, the device has a construction in which the lead pins
3
on the leadframe are fixed with the semiconductor chip
1
and an adhesive layer
6
and together with a bonding wire
4
, they are molded with a resin
5
. In
FIG. 3
, the device has a construction in which a semiconductor chip
1
is mounted on a die pad, electrode
8
is fixed with an adhesive layer
6
, the spaces between semiconductor chip
1
and an electrode
8
and between the electrode
8
and lead pins
3
are each connected with bonding wires
4
, and they are molded with a resin
5
.
In the adhesive layer in the resin-molded type semiconductor devices shown in
FIGS. 1
to
3
, the use of an adhesive tape to which a conventional adhesive is applied has the problems that the generated gas stains the lead to cause deterioration of the adhesive strength or causes generation of package crack, bacuse of insufficient thermal resistance.
The present invention has been made in the light of such situations associated with the prior arts and in order to improve such situations. An object of the present invention is, therefore, to provide an adhesive tape and a liquid adhesive for electric parts having sufficient thermal resistance and reliability.
SUMMARY OF THE INVENTION
An adhesive tape for electronic parts according to the first aspect of the present invention comprises an adhesive layer composed of a polyimide resin comprising a repeating unit represented by the following formula (1), provided on at least one surface of a heat resistance film:
wherein X is —SO
2
— or —C(═O)—OCH
2
CH
2
O—C(═O)—, and R
1
, R
2
, R
3
and R
4
are independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.
An adhesive tape for electronic parts according to the second aspect of the present invention comprises an adhesive layer composed of a polyimide resin comprising a repeating unit represented by the above formula (1), provided on at least one surface of a release film.
A liquid adhesive for electronic parts according to the present invention comprises a polyimide resin comprising a repeating unit represented by the above formula (1) dissolved in an organic solvent.
REFERENCES:
patent: 5300627 (1994-04-01), Kunimune
patent: 5508357 (1996-04-01), Matsuura
patent: 5510425 (1996-04-01), Matsuura
patent: 5663287 (1997-09-01), Oka
Nishigaya Takeshi
Oka Osamu
Yamanashi Fumiyoshi
Davis Jenna
McDermott & Will & Emery
Tomoegawa Paper Co. Ltd.
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