Semiconductor device manufacturing: process – Making device or circuit responsive to nonelectrical signal – Responsive to electromagnetic radiation
Reexamination Certificate
1998-07-16
2003-05-27
Wilczewski, Mary (Department: 2822)
Semiconductor device manufacturing: process
Making device or circuit responsive to nonelectrical signal
Responsive to electromagnetic radiation
C438S075000, C257S215000
Reexamination Certificate
active
06569703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a solid-state image sensing device provided with a light shielding film and a solid-state image sensing device in which the efficiency of condensing beams to a light-sensitive sensor is enhanced.
2. Description of the Related Art
A solid-state image sensing device which represents a charge coupled device (CCD) is a device for photographing an image formed by light and others, a light-sensitive sensor part for photoelectric transfer is formed on the surface of a substrate such as a silicon substrate and a light shielding film for preventing light from being incident on the substrate except the above light-sensitive sensor is formed.
In such a solid-state image sensing device, a metal sputtered film is normally used for a light shielding film. That is, heretofore, a metal film, particularly an aluminum film is formed by sputtering, patterned by dry etching using a photoresist mask, a part over a light-sensitive sensor part is open and a light shielding film is formed on a part except the light-sensitive sensor.
Recently, the miniaturization of a solid-state image sensing device and the densification of a picture element are more accelerated, hereby, the area of a light-sensitive sensor part is reduced and the deterioration of characteristics such as the deterioration of sensitivity and the increase of a smear is caused.
For measures for the deterioration of sensitivity, measures such as an on-chip lens is provided and the efficiency of condensing beams to a light-sensitive sensor is enhanced are proposed and executed.
For measures for a smear, normally, measures such as a light shielding film is formed with the film extended even over a light-sensitive sensor part are taken.
However, as the difference in a level of a transfer electrode and others is relatively increased because of miniaturization and the densification of a picture element even in a solid-state image sensing device in which the above on-chip lens is provided and the efficiency of condensing beams is enhanced, the degree of the covering of a light shielding film formed by sputtering aluminum is not enough and particularly, if a substrate has large difference in a level, the degree of sufficient covering is sometimes not realized. When the degree of covering becomes insufficient because of the densification of a picture element as described above and a light shielding function cannot be sufficiently achieved, a component which transmits light to a transfer electrode is increased and characteristics against a smear are deteriorated.
As a picture element is densified, difference in a level in a light-sensitive sensor part is increased, hereby, uniformity in working an opening is deteriorated, the degree of covering is further deteriorated, the minute nonuniformity of sensitivity is caused and characteristics as a image sensing device are deteriorated. Further, a clamping error may be caused by the transmission of an optical black beam.
As for a solid-state image sensing device in which a light shielding film is extended up to over a light-sensitive sensor part, when a light shielding film is extended as described above, the area of an opening over the light-sensitive sensor part is naturally reduced, the efficiency of condensing beams is deteriorated, sensitivity is deteriorated after all and the above miniaturization and the densification of a picture element cannot be realized.
SUMMARY OF THE INVENTION
The present invention is made in view of the above conditions and the object is to provide a solid-state image sensing device in which the efficiency of condensing beams to a light-sensitive sensor and sensitivity are enhanced and its manufacturing method.
To solve the above problems, a method of manufacturing a solid-state image sensing device according to the present invention and disclosed in claim
1
wherein a light-sensitive sensor part for photoelectric transfer is formed on the surface of a substrate and a light shielding film for preventing light from being incident on the substrate except the above light-sensitive sensor part is formed is provided with a process for forming a transfer electrode on the substrate via an insulating film and forming a planarized film for covering an interlayer insulating film after the interlayer insulating film for covering the transfer electrode is further formed, a process for selectively etching only the location of the planarized film to be a light shielding area for forming the above light shielding film and forming a concave portion, a process for forming a groove deep enough to reach the vicinity of the surface of the substrate by etching the planarized film over the periphery of the above light-sensitive sensor part and near the side of the transfer electrode and a process for forming the light shielding film by burying the material of the light shielding film in the concave portion and inside the groove.
According to the above manufacturing method, as the concave portion is formed in only the location of the planarized film to be the light shielding area, the groove deep enough to reach the vicinity of the surface of the substrate is formed over the periphery of the light-sensitive sensor part and near the side of the transfer electrode and afterward, the light shielding film is formed by burying the material of the light shielding film in the concave portion and inside the groove, the light shielding film without an extended part is formed, hereby, the efficiency of condensing beams to the light-sensitive sensor part is enhanced and sensitivity is enhanced.
To solve the above problems, a method of manufacturing a solid-state image sensing device wherein a light-sensitive sensor part for photoelectric transfer is formed on the surface of a substrate and a light shielding film for preventing light from being incident on the substrate except the above light-sensitive sensor part is formed is provided with a process for forming a transfer electrode on the substrate via an insulating film and forming a first planarized film for covering an interlayer insulating film after the interlayer insulating film for covering the transfer electrode is further formed, a process for forming a groove deep enough to reach the vicinity of the surface of the substrate by etching the first planarized film over the periphery of the above light sensitive sensor part and near the side of the transfer electrode, a process for forming a first light shielding film by burying the material of the light shielding film inside the groove, a process for forming a second planarized film for covering the first planarized film on the first planarized film, a process for forming a concave portion with the upper surface of the first light shielding film opposite to the outside by selectively etching only the location of the second planarized film to be a light shielding area for forming the light shielding film and a process for forming a second light shielding film by burying the material of the light shielding film inside the concave portion and hereby, acquiring a light shielding film made of the first and second light shielding films.
According to the above manufacturing method, as a groove deep enough to reach the vicinity of the surface of a substrate is formed in a first planarized film over the periphery of a light-sensitive sensor part and near the side of a transfer electrode, a first light shielding film is formed by burying the material of the light shielding film inside the groove, next, a concave portion is formed in only the location of a second planarized film to a light shielding area, afterward, a second light shielding film is formed by burying the material of the light shielding film inside the concave portion and hereby, a light shielding film made of the first and second light shielding films is acquired, particularly, a light shielding film without a protruded part is formed by the first light shielding film embedded inside the groove, hereby, the efficiency of condensing
Sonnenschein Nath & Rosenthal
Sony Corporation
Wilczewski Mary
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