Semiconductor device manufacturing: process – Chemical etching – Combined with the removal of material by nonchemical means
Reexamination Certificate
2001-09-25
2003-10-28
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Chemical etching
Combined with the removal of material by nonchemical means
C438S459000
Reexamination Certificate
active
06638865
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-309742, filed Oct. 10, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a manufacturing method of a semiconductor device and more particularly to a method applied to a manufacturing process of a semiconductor chip obtained by adhering a film-like die bonding agent to a semiconductor chip which is made thin and formed into a discrete form by a dicing before grinding method.
2. Description of the Related Art
In order to simplify the step of mounting a semiconductor chip (pellet) on a metal frame or a printed circuit board such as organic substrate, a semiconductor chip having a film-like die bonding agent adhered to the rear surface thereof or a so-called semiconductor chip with an adhesive agent is used.
Conventionally, the semiconductor chip with the adhesive agent is formed by the steps as shown in
FIGS. 1A
to
1
E. That is, first, as shown in
FIG. 1A
, a film-like adhesive agent (adhesive film)
12
is adhered by laminating, for example, to the entire portion of the rear surface (the rear surface opposite to the element forming surface) of a semiconductor wafer
11
in which formation of elements is completed.
Then, after a portion of the adhesive film
12
which is not adhered to the wafer
11
is removed, an adhesive film surface thereof is adhered to a dicing tape
14
mounted on a wafer ring
13
as shown in FIG.
1
B.
After this, as shown in
FIG. 1C
, the wafer
11
is diced together with the adhesive film
12
along dicing lines
16
by use of a dicer
15
.
Next, as shown in
FIG. 1D
, each of semiconductor chips is picked up by use of a pickup needle, for example, from the wafer which has been diced and formed into a discrete form and a semiconductor chip
17
with an adhesive agent is formed as shown in FIG.
1
E.
Then, the surface of the semiconductor chip
17
with the adhesive agent on the adhesive film
12
side is pressed against a metal frame or a printed circuit board such as organic substrate and it is mounted on the metal frame or organic substrate.
In recent years, it is desired to make thin the semiconductor chip in order to mount the semiconductor chip on a card-like thin package or reduce the mounting area by stacking and mounting a plurality of semiconductor chips. However, if the rear surface of the wafer on which elements have been formed is ground to make the wafer thin and the wafer which is made thin is diced and divided into individual semiconductor chips, the wafer may be cracked or the rear surface chipping occurs at the time of dicing or transfer of the wafer between the steps.
A method for suppressing breakage of the wafer or occurrence of the rear surface chipping caused by making the semiconductor chip thin to a minimum degree is a dicing before grinding (DBG which is an abbreviation of Dicing Before Grinding) method described in U.S. Pat. No. 4,722,130, for example. In the dicing before grinding method, the wafer is simultaneously made thin and formed into a discrete from by grinding the rear surface of the wafer after cuts (grooves) are made to a preset depth in the element forming surface of the wafer.
However, in order to form the semiconductor chips with the adhesive agent described above by use of the semiconductor chips which are made thin and formed into a discrete form by the dicing before grinding method, it becomes necessary to adhere an adhesive film to the divided semiconductor chips by laminating, for example, and then dice only the adhesive film, and thus the manufacturing process becomes complicated.
To prevent the manufacturing process from becoming complicated, a manufacturing method as shown in
FIGS. 2A and 2B
is proposed. In the method, as shown in
FIG. 2A
, adhesive films
22
having substantially the same size as the semiconductor chip are previously affixed to a portion of a metal frame or a printed circuit board such as organic substrate
21
on which the semiconductor chip will be die-mounted.
Next, as shown in
FIG. 2B
, semiconductor chips
23
are pressed against and die-bonded on and mounted on the respective adhesive films
22
.
However, with the above manufacturing method, since the adhesive films
22
and semiconductor chips
23
are separately pressed against, positional deviation tends to occur between the adhesive film
22
and the semiconductor chip
23
. Therefore, there occurs a problem that the precision of the mounting position is lowered. Accordingly, it becomes necessary to newly introduce a highly precise film sticking machine or the like in order to press the adhesive films
22
against and mount the same on the metal frame or printed circuit board
21
with high positioning precision.
As described above, the conventional manufacturing method of the semiconductor device for forming the semiconductor chip with the adhesive agent has a problem that the manufacturing process becomes complicated if the dicing before grinding method is used. Further, if an attempt is made to prevent the manufacturing process from becoming complicated, positional deviation tends to occur between the adhesive film and the semiconductor chip, the precision of the mounting position is lowered and a highly precise film sticking machine is required.
BRIEF SUMMARY OF THE INVENTION
According to an aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising: dicing a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips to an adhesive film having a first surface and a second surface; the film comprising thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and the first surface of the adhesive film being adhered to the rear surface of the semiconductor chips; removably affixing the second surface of the adhesive film to a dicing tape; and removing any excess portions of the adhesive film disposed between the respective semiconductor chips.
According to another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a first surface of a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips on an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and is depolymerized by UV rays whereby a first surface of the adhesive film becomes adhered to the semiconductor chips; affixing to the second surface of the adhesive film a dicing tape; applying UV rays to the wafer from above to cause a depolymerization reaction on any excess portions of the adhesive film disposed between the respective semiconductor chips; and removing the depolymerized adhesive film.
According to still another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips on an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and subjecting the excess adhesive film to crosslinking and polymerization reactions by applying UV rays; affixing the second surface o
Frommer & Lawrence & Haug LLP
Kabushiki Kaisha Toshiba
Nelms David
Pan Grace L.
Vu David
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