Method of manufacturing semiconductor device in which...

Details Method of manufacturing semiconductor device in which... Method of manufacturing semiconductor device in which...

1997-04-09

2001-09-11

Huff, Mark F. (Department: 1756)

Radiation imagery chemistry: process, composition, or product th

Imaging affecting physical property of radiation sensitive...

Making electrical device

C430S311000, C430S330000

Reexamination Certificate

active

06287750

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device, and more particularly to a method of forming an opening for a conductive layer or a bonding pad in an interlayer insulating film or a passivation layer which has a lamination structure composed of an inorganic insulating layer as a moisture proofing layer and a polyimide layer as a buffer material layer.
2. Description of the Related Art
A first conventional example of a method of forming an opening for a bonding pad in a lamination structure of a polyimide layer and an inorganic insulating layer will be described with reference to
FIGS. 1A
to
1
F. The lamination structure is used as a passivation layer. The method is disclosed in Japanese Laid Open Patent Disclosure (JP-A-Heisei 4-179124: reference 1).
First, referring to
FIG. 1A
, a bonding pad
102
is formed on a semiconductor substrate
101
. Next, referring to
FIG. 1B
, a silicon nitride layer
103
as the inorganic insulating layer is formed by a plasma CVD method to cover the bonding pad
102
and the substrate
101
. Next, referring to
FIG. 1C
, a photo-sensitive polyimide layer
104
is spin-coated on the silicon nitride layer
103
. Subsequently, the substrate
101
is pre-baked in a nitrogen atmosphere to harden the photo-sensitive polyimide layer
104
.
Next, referring to
FIG. 1D
, exposure is performed of the photo-sensitive polyimide layer
104
using a negative-type photo-mask
105
. Subsequently, referring to
FIG. 1E
, development is performed using a dedicated developing solution. As a result, a part of the photo-sensitive polyimide layer
104
which has not been exposed in the process shown in
FIG. 1D
is developed and removed. In this manner, an opening
106
is formed in the photo-sensitive polyimide layer
104
. Finally, referring to
FIG. 1F
, the silicon nitride layer
3
is dry-etched in a fluoric system atmosphere using the photo-sensitive polyimide layer
104
as an etching mask. Then, heat treatment is performed of the polyimide layer
104
in a nitrogen atmosphere. As a result, an opening
107
to the bonding pad
102
is formed in the passivation layer (
103
and
104
).
In this manner, in the first conventional example shown in
FIGS. 1A
to IF, the opening
107
to the bonding pad
102
through the passivation layer (
103
and
104
) is formed with a single photo-lithography process.
However, in the first conventional method shown in
FIGS. 1A
to IF, the buffer coat performance of the photosensitive polyimide layer
104
is inferior. For this reason, there is a problem in that decrease of reliability is caused. Also, there is another problem in that the manufacturing cost is increased because the photo-sensitive polyimide is higher in price than un-photosensitive polyimide.
Next, a second conventional example of a method of forming an opening to a bonding pad in a semiconductor device which uses a lamination structure composed of a polyimide layer and an inorganic insulating layer will be described with reference to
FIGS. 2A
to
2
I. This second conventional method is disclosed in Japanese Laid Open Patent Disclosure (JP-A-Heisei 5-190532: reference 2). The lamination structure is used as a passivation layer.
First, referring to
FIG. 2A
, like the process shown in
FIG. 1A
, a bonding pad
202
is formed on a semiconductor substrate
201
. Next, referring to
FIG. 2B
, a silicon nitride layer
203
as the inorganic insulating layer is formed on the bonding pad
202
and the substrate
201
by the plasma CVD method, as in the process shown in FIG.
1
B. Subsequently, referring to
FIG. 2C
, a polyimide layer
204
is spin-coated on the silicon nitride layer
203
and then is pre-baked in a nitrogen atmosphere so that the polyimide layer
204
is hardened. Thereafter, referring to
FIG. 2D
, a negative-type photo-resist layer
205
is spin-coated on the polyimide layer
204
.
Next, referring to
FIG. 2E
, exposure is performed of the photo-resist layer
205
using a positive-type photo-mask
206
. Then, referring to
FIG. 2F
, development is performed of the photo-resist layer
205
using a dedicated developing solution. As a result, a part of the photo-resist layer
205
which has been exposed in
FIG. 2E
is developed and removed. In this manner, an opening
207
is formed through the photo-resist layer
205
.
Next, referring to
FIG. 2G
, the polyimide layer
204
is selectively etched by organic solvent to form an opening
208
, using the photo-resist layer
205
as an etching mask.
Next, referring to
FIG. 2H
, the silicon nitride layer
203
is dry-etched in a fluoric system atmosphere to form an opening
209
using the photoresist layer
205
and polyimide layer
204
as an etching mask.
Finally, referring to
FIG. 2I
, the photo-resist layer
205
is removed using a wet etching method. Subsequently, heat treatment is performed of the polyimide layer
204
in a nitrogen atmosphere. Thus, the opening
209
to the bonding pad
202
is formed in the passivation layer (
203
and
204
).
In this manner, in the second conventional method shown in
FIGS. 2A
to
2
I, the opening
209
through the passivation layer (
203
and
204
) to the bonding pad
202
is also formed in a single photo-lithography process. Further, damage of the surface of the polyimide layer
204
due to the dry etching is restrained and a sticking error that trace of absorbed collets is left on the surface of the polyimide layer
204
is reduced in the mount.
However, in the second conventional method shown in
FIGS. 2A
to
2
I, when the silicon nitride layer
203
is dry-etched, the surface of the photo-resist layer
205
is hardened. For this reason, there is a problem in that the photo-resist layer
205
cannot be removed by a wet etching method. Further, if an oxygen plasma ashing method is used to remove the hardened photo-resist layer
205
, there is another problem in that the polyimide layer
204
is also removed. That is, this method is lacking in realizability.
A third conventional example of a manufacturing method of a semiconductor device in which a lamination structure composed of a polyimide layer and the inorganic insulating layer is used will be described with reference to
FIGS. 3A
to
3
I. This conventional method is disclosed in Japanese Laid Open Patent Disclosure (JP-A-Heisei 5-190532: reference 2). The lamination structure is used as the interlayer insulating layer.
First, referring to
FIG. 3A
, an aluminum wiring layer
302
is formed on a semiconductor substrate
301
. Subsequently, referring to
FIG. 3B
, a silicon nitride layer
303
as the inorganic insulating layer is formed by a plasma CVD method to cover the aluminium wiring layer
302
and the semiconductor substrate
301
. Next, referring to
FIG. 3C
, a polyimide layer
304
is spin-coated, and then is pre-baked in a nitrogen atmosphere to be hardened in the film quality. Then, referring to
FIG. 3D
, a negative-type photo-resist layer
305
is spin-coated on the polyimide layer
304
.
Next, referring to
FIG. 3E
, exposure is performed of the photo-resist layer
305
using a photo-mask
306
. Then, referring to
FIG. 3F
, when development is performed using a dedicated developing solution, a part of the photo-resist layer
305
which has been exposed in the process shown in FIG.
3
E is developed and removed. As a result, an opening
307
is formed by photo-resist layer
305
.
Next, referring to
FIG. 3G
, the polyimide layer
304
is selectively etched in an oxygen system atmosphere such that an opening
308
is formed, using the photo-resist layer
305
as an etching mask. Subsequently, referring to
FIG. 3H
, dry etching is performed of the inorganic insulating layer
303
in a fluoric system atmosphere such that an opening
309
is formed, using the photo-resist layer
305
and the polyimide layer
304
as an etching mask.
Finally, referring to
FIG. 3I
, the photo-resist layer
305
is removed by a wet etching method. Subsequently, heat treatment is performed of the polyimide layer
304

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