Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Encapsulating
Reexamination Certificate
2001-09-07
2003-06-10
Cuneo, Kamand (Department: 2829)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Encapsulating
C438S115000, C438S906000
Reexamination Certificate
active
06576500
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to plasma-processing apparatus and method for plasma-cleaning pads on a chip and pads on a board to which chips are mounted, and a plasma-processed board, and further relates to a chip mounting method employing the plasma-processing method and a chip mounted assembly.
BACKGROUND OF THE INVENTION
A plasma-cleaning process, which is known, removes a dirt on a pad at the sides of a position for mounting a chip on a printed circuit board or on a pad on the upper surface of the chip prior to a wire bonding to the pad. In the plasma-cleaning process, the board including the chip mounted thereon is placed in a chamber of a plasma-processing apparatus, in which plasma is generated, and ions and neutral particles called radicals collide with the surface of the chip to remove the dirt on the board. After the plasma-cleaning process, the pad on the chip and the board are connected with wires by a wire bonding apparatus. Finally, the chip and the wires are covered with a resin by mold sealing.
FIG. 7
is a side view of a board including a conventional resin mold
6
′. A chip
2
is mounted on a chip-mounting position
1
′ of a board
1
. A Pad
3
at the side of the position
1
′ is connected to a pad
4
on the upper surface of the chip
2
with a wire. The resin mold
6
′ is provided for protecting the chip
2
and the wire
5
by mold sealing.
As denoted by the solid line in
FIG. 7
, the resin mold
6
′ flows wide and flattens around the chip
2
but is not domed. This causes the top of the wire
5
to be exposed out of the resin mold
6
′. A desired shape of the resin mold
6
is denoted by the dotted line keeping a dome shape to encapsulate the chip and wire
5
.
The reason why the resin mold
6
′ is not domed but flattened is explained below. In a conventional plasma-processing apparatus, the board
1
has an entire surface exposed for plasma for the plasma-cleaning. As being plasma-cleaned, the entire surface has an increased wetting property. Accordingly, the resin used with resin mold
6
′ has increased adhesive properties. And therefore, the molded form of the resin may thus flow extensively around the chip and flatten over the upper surface of the board
1
before being cured down. As a result, the resin mold
6
′ has a flat shape as denoted by the solid line in FIG.
7
.
SUMMARY OF THE INVENTION
A plasma-processing apparatus for plasma-cleaning a board having a chip and a pad-disposed area around the chip includes a chamber for accommodating the board, an electrode disposed at the chamber for generating plasma in the chamber by a high frequency voltage applied to the electrode; a table for supporting the board in the chamber, and a masking member provided above the board and having an opening for exposing the chip and the pad-disposed area to the plasma.
A plasma-processing method using the plasma-processing apparatus includes a process of applying a voltage to the electrode to generate plasma in the chamber; and a process of exposing the chip and the pad area to the plasma through the opening of the masking member for performing the plasma-process.
REFERENCES:
patent: 6069024 (2000-05-01), Murakami
patent: 6117708 (2000-09-01), Wensel
patent: 6261869 (2001-07-01), Radford et al.
patent: 11111694 (1999-04-01), None
Furukawa Ryota
Nagadome Ryuji
Cuneo Kamand
Geyer Scott B.
Parkhurst & Wendel L.L.P.
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