Abrading – Abrading process – Combined abrading
Reexamination Certificate
1999-11-01
2002-05-14
Rose, Robert A. (Department: 3723)
Abrading
Abrading process
Combined abrading
C451S065000
Reexamination Certificate
active
06386956
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to flattening polishing devices and flattening polishing methods for flatly polishing plated films or insulating films formed on, for example, wafer surfaces.
2. Description of the Related Art
FIGS. 10A
to
10
F show sectional side elevation views illustrating manufacturing processes for a metal interconnection type board.
An interconnection pattern
2
composed of copper (Cu) is formed on a surface of a wafer
1
composed of silicon so as to coat the surface of the wafer
1
including the interconnection pattern
2
with an insulating film
3
composed of silicon dioxide (SiO
2
) (FIG.
10
A).
Further, conducting holes
4
for a laminated interconnection pattern are etched to be formed in the insulating film
3
(FIG.
10
B), so as to coat the surface of the insulating film
3
including inner surfaces of the conducting holes
4
with a barrier film
5
composed of tantalum (Ta) or titanium (Ti) or the like (FIG.
10
C), and seed films
6
composed of copper (Cu) are formed by sputtering(FIG.
10
D). Further, a film
7
for the laminated interconnection pattern composed of copper (Cu) is plated in a comparatively thick condition and is formed in such a manner that inner portions of the conducting holes
4
are completely blocked (FIG.
10
E). Thereafter, unnecessary films
7
for the laminated interconnection pattern on the barrier film
5
are machined to be polished so as to remove them and a laminated interconnection pattern
8
is formed so as to have a final metal interconnection type board
9
(FIG.
10
F).
FIG. 12
shows a sectional side elevation view illustrating a manufacturing process for an element separation type board.
Elements
12
are formed on a surface of a wafer
11
composed, for example, of silicon so as to coat the surface of the wafer
11
containing the elements
12
with stopper films
13
composed of silicon nitride (SiN). Further, element separating trench holes
14
are etched to be formed from the stopper films
13
over to the wafer
11
so as to coat the holes, in a relatively thick condition, with an insulating film
15
composed of silicon dioxide (SiO
2
) in such a manner that an inner portion of the trench holes
14
are completely blocked (FIG.
12
A). Thereafter, unnecessary insulating films
15
on the stopper films
13
are machined to be polished so as to remove them and trenches
16
are formed so as to have the final element separation type board
17
(FIG.
12
B).
In a polishing process, when manufacturing the above respective boards
9
and
17
, the flattening polishing device is used.
FIG. 14
shows a perspective view illustrating an outline of a related flattening polishing device.
This flattening polishing device
20
is provided with a rotatable surface plate
22
in a shape of a disk on a top face of which a polishing cloth
21
is stuck, a rotatable and vertically (along the Z axis) movable mounting plate
23
in a shape of a disk for holding wafers
1
and
11
by bottom faces thereof and a nozzle
24
for supplying a polishing liquid P on the polishing cloth
21
.
In such constitution, first, the surfaces of the wafers
1
and
11
on which the films
7
and
15
are formed are faced downward, a reverse face of the wafer
1
is bonded or is vacuum-adsorbed to the bottom face of the mounting plate
23
. Next, while the surface plate
22
and the mounting plate
23
are rotated, the polishing solution P is supplied on the polishing cloth
21
from the nozzle
24
. Further, the mounting plate
23
is lowered, the surfaces of the wafers
1
and
11
are forcedly pressed on the polishing cloth
21
so as to polish the films
7
and
15
formed on the surfaces of the wafers
1
and
11
.
In an initial stage of the polishing process on the occasion of respectively manufacturing the above described boards
9
and
17
, only a kind of film that is respectively the film
7
for the laminated interconnection pattern or the insulating film
15
may well be polished. However, in the final stage, since it is respectively necessary to expose the barrier film
5
or the stopper film
13
, two kinds of films should concurrently be polished, that is, not only the film
7
for the laminated interconnection pattern or the insulating film
15
, but also the barrier film
5
or the stopper film
13
.
When the films of different kinds, in other words, the films of different hardness are polished using the related flattening polishing device
20
, there are such cases where defects such as dishing, erosion (thinning) recess, scratch, chemical damage, overpolishing, and underpolishing are formed.
FIG. 11
shows a sectional side elevation view illustrating defects in the metal interconnection type board
9
and
FIG. 13
shows a sectional side elevation view illustrating defects in the element separation type board
17
.
FIG.
11
A and
FIG. 13A
are examples of the dishing, wherein at central portions of the film
7
for the laminated interconnection board and of the insulating film
15
over broad areas are caved in due to too much polishing so as to result in a shortage of sectional areas for the laminated interconnection pattern
8
and the trench
16
, to eventually become the defects.
FIG.
11
B and
FIG. 13B
are examples of the erosion (thinning), wherein portions whose pattern density are high are caved in due to excessive polishing so as to result in a shortage of sectional areas for the laminated interconnection pattern
8
and the trench
16
, to eventually become the defects.
FIG.
11
C and
FIG. 13C
are examples of the recesses, wherein a side of the laminated interconnection pattern
8
and a side of the trench
16
are lowered at boundaries between the laminated interconnection pattern
8
and the insulating films
3
and between the trench
16
and the stopper film
13
so as to generate level differences, to consequently become defects.
FIG. 11D
is an example of the scratch or the chemical damage, wherein an open circuit or short circuit or a failure in a resistance value of the laminated interconnection pattern
8
is generated, to eventually become faults.
FIG. 13D
is an example such as the overpolishing and the underpolishing, wherein due to a shortage in relation to a set removal amount of the insulating films
15
, the insulating films
15
remain on the surface of the board to consequently become defects, or due to an excessive amount in relation to the set removal amount of the insulating films
15
the sectional area of the trench
16
results in shortage to eventually become defects.
SUMMARY OF THE INVENTION
The present invention is planned and constituted according to the above-described circumstances, and it is an object of the present invention to provide a flattening polishing device and a flattening polishing method capable of conducting a flattening polishing with high accuracy and no defects.
In the present invention, and in the flattening polishing device for flatly polishing a surface of an object to be polished, the above-described object can be attained by providing the device with first polishing means and second polishing means which are coaxially disposed, moving means for moving the respective polishing means relative to each other in an axial direction and rotary means for rotating the respective polishing means around a shaft.
Further, in the present invention, and in the flattening polishing method for flatly polishing a surface of an object to be polished, the above-described object can be attained by providing the method with a process for rotating two polishing means disposed in shapes of concentric circles, a process for protruding a polishing surface of one of the polishing means more than a polishing surface of the other polishing means to a side of the object to be polished, a process for polishing the surface of the object to be polished by one of the polishing means, a process for protruding the polishing surface of the other polishing means more than the polishing surface of the one of the polishing means to the si
Ihira Takuo
Sato Shuzo
Kananen, Esq. Ronald P.
Rader & Fishman & Grauer, PLLC
Rose Robert A.
Sony Corporation
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