Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
1999-03-15
2001-03-27
Picardet, Kevin M. (Department: 2823)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S113000, C438S462000, C438S613000, C257S620000
Reexamination Certificate
active
06207473
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method manufacturing a semiconductor wafer having circuit elements integrally fabricated on a substrate, a semiconductor wafer manufactured by this method, a method of manufacturing semiconductor chips from the semiconductor wafer, the semiconductor chips manufactured by this method, and an IC card provided with the semiconductor chip.
BACKGROUND ART
FIG. 7
is an enlarged view of an insulating substrate
20
having a prescribed wiring pattern with a semiconductor chip
10
mounted by a so-called chip-on-board method. In an example of the chip-on-board method, an anisotropically conductive film
30
is interposed between insulating substrate
20
having conductor bumps
21
formed protruding upward and semiconductor chip
10
having electrode bumps
11
protruded from a main surface
10
a,
and these are heated and pressed so that conductor bumps
21
and electrode bumps
11
are conducted and connected.
As can be seen best from
FIG. 7
, anisotropically conductive film
30
has such a structure in that conductive particles
32
are dispersed in an adhesive resin film
31
, and conductor bumps
21
and electrode bumps
11
are conducted and connected to each other as conductive particles
32
are interposed therebetween. An area of the main surface
10
a
of semiconductor chip
10
where electrode bumps
11
are not formed is adhered to insulating substrate
20
by the adhesiveness of resin film
31
provided when anisotropically conductive film
30
is heated, melt and thereafter solidified. At this time, the conductive particles
32
are dispersed in resin film
31
and separate from each other, and therefore insulation in this region is maintained. In the above described method of mounting, by only a simple operation of pressing semiconductor chip
10
and insulating substrate
20
to each other with anisotropically conductive film
30
interposed, it is possible to mount semiconductor chip
10
on insulating substrate
20
while attaining electrical conduction only at necessary portions. Therefore, as compared with mounting of semiconductor chip
10
on insulating substrate
20
through so called chip bonding and wire bonding, the method is very simple and convenient.
When semiconductor chip
10
is to be mounted on insulating substrate
20
utilizing anisotropically conductive film
30
however, it is necessary to prepare very small anisotropically conductive film having 4 sides each being about a few mm corresponding to the size of semiconductor chip
10
to be mounted, in the same number as the number of semiconductor chips
10
to be mounted. Further, prior to mounting of semiconductor chips
10
, it is necessary to place anisotropically conductive films
30
one by one on conductor bumps
21
of insulating substrate
20
or to stick the films one by one on the main surface
10
a
of semiconductor chips
10
. Thus, the conventional method of mounting utilizing anisotropically conductive film
30
has poor workability in preparation preceding mounting of the semiconductor chips
10
.
In view of the foregoing, a method has been proposed in which anisotropically conductive film
30
is stuck entirely over a circuit element forming region of a semiconductor wafer on which a plurality of circuit elements, which are to be the semiconductor chips
10
, are formed, and the anisotropically conductive film
30
is diced simultaneously with dicing of the circuit elements. In the above described method, when the circuit elements are divided into individual semiconductor chips
10
, anisotropically conductive film
30
is stuck on main surface
10
a,
and the method has an advantage that any special preparation is not necessary prior to mounting of the semiconductor chip
10
.
Generally, a semiconductor wafer has so called scribe lines formed at appropriate positions, and the wafer is diced into circuit elements by a diamond cutter, for example, using the scribe lines as reference marks. The scribe line is formed, for example, simultaneously with the step of forming a pattern of a passivation film. Now, as described above, anisotropically conductive film
30
has such a structure in that a number of conductive particles
32
are dispersed in resin film
31
. Therefore, the color of anisotropically conductive film
30
is milky white. When anisotropically conductive film
30
is stuck on the semiconductor wafer, it becomes necessary to recognize silver scribe lines formed of SiN or the like through milky white anisotropically conductive film. This causes difficulty in visually recognizing the scribe lines, and hence difficulty in dicing the circuit elements to obtain desired semiconductor chips
10
.
DISCLOSURE OF THE INVENTION
An object of the present invention is to solve the above described problem of the prior art, and to enable dicing of circuit elements as desired even when an anisotropically conductive film is stuck on a semiconductor wafer having a plurality of circuit elements formed thereon.
In order to attain the above described objects, the present invention provides the following technical measure.
More specifically, according to a first aspect of the present invention, the method of manufacturing a semiconductor wafer includes the steps of integrally fabricating a plurality of circuit elements on a substrate, forming electrode bumps on electrode pads conducting to respective circuit elements, forming scribe lines or scribe line marks at prescribed positions of the substrate, and sticking an anisotropically conductive film to cover respective electrode bumps and scribe lines or scribe line marks, wherein the step of forming respective electrode banks and the step of forming the scribe lines or scribe line marks are performed simultaneously.
When a semiconductor chip is to be mounted on the substrate using the anisotropically conductive film, it is necessary to form an electrode bump protruding from the main surface of the semiconductor chip on the electrode pad which is conducted to the circuit element. The electrode bump is formed on the electrode pad after a prescribed wiring pattern including the electrode pad is formed. According to the manufacturing method described above, the step of forming respective electrode bumps and the step of forming the scribe lines or scribe line marks are performed simultaneously. More specifically, a new step is not necessary for forming the scribe lines or the scribe line marks, and it is possible to form the scribe lines or scribe line marks at prescribed positions in the step essential in manufacturing the semiconductor wafer.
In a preferred embodiment, the step of forming respective electrode bumps and scribe lines or scribe line marks includes the steps of forming an insulating layer protecting the circuit elements while exposing upper surfaces of the electrode pads, forming a barrier metal layer entirely over the circuit element forming region on the substrate, forming a photo resist layer such that portions corresponding to regions where respective electrode pads are formed and portions on which the scribe lines or scribe line marks are to be formed can been seen, forming a metal layer at portions where the photo resist layer is not formed, and removing the photo resist layer and the barrier metal layer.
In the manufacturing method described above, by dipping the substrate on which the photo resist layer has been formed in a solution containing metal ions, for example, and by applying electric power using the barrier metal layer as a negative electrode, a metal layer is grown on regions where the photo resist layer is not formed, and in this manner, respective electrode bumps and the scribe lines or scribe line marks can be formed simultaneously. More specifically, simply by not forming the photo resist layer at portions where the scribe lines or scribe line marks are to be formed when the photo resist layer is formed, the scribe lines or the scribe line marks can be formed simultaneously with the electrode bumps.
In a preferred embodiment, the electrode bumps and the scribe li
Hirai Minoru
Horio Tomoharu
Miyata Osamu
Ueda Shigeyuki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Collins D. M.
Picardet Kevin M.
Rohm & Co., Ltd.
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