Etching a substrate: processes – Nongaseous phase etching of substrate – Etching inorganic substrate
Reexamination Certificate
2000-07-18
2003-01-21
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Nongaseous phase etching of substrate
Etching inorganic substrate
C216S012000, C216S024000, C216S041000, C216S049000, C216S051000, C216S083000, C430S005000, C438S022000, C438S027000, C438S029000, C438S031000, C438S032000
Reexamination Certificate
active
06508949
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Japanese Patent Application No. 11-207537, filed Jul. 22, 1999, the entire subject matter of which is incorporated herein of reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for correcting characteristics of an attenuated phase-shift mask. Specifically, the characteristics of the attenuated phase-shift mask is modified by changing a thickness or a composition of a mask pattern layer in response to a particular data.
2. Description of the Related Art
With an increase in the level of integration of semiconductor integrated circuits, there have been rapid advances in minimizing micropatterns used for circuitry, so that a high resolution technology and a sufficient depth of focus (DOF) has been required Therefore, a conventional photomask
1
shown in
FIG. 14
, which includes a light shielding layer
16
formed on a glass substrate
2
to form micropatterns, cannot satisfy the requirements of the resolution and the DOF in a high integration lithography process because the light passing through the mask
1
is diffracted.
To resolve this problem, a variety of types of phase-shift mask has been proposed to date, including an attenuated phase-shift mask, a Lebenson-type phase-shift mask, a phase-shift mask having an optical proximity correction, a self-align phase-shift mask and a transmittance-type phase-shift mask. Specifically, the attenuated phase-shift mask is widely used because of its simple construction.
The attenuated phase-shift mask
10
shown in
FIG. 2
includes a attenuated layer
14
which is formed on a glass substrate
12
, and a light shielding layer
16
form on parts of the attenuated layer
14
. Referring to
FIG. 15
, when light passes through the mask
10
, a phase &thgr;
1
of the light that passes through the attenuated layer
14
is shifted from a phase &thgr;
2
of the light that passes only through the substrate
12
for about 180 degree because the transmitting speed of the light that passed through the attenuated layer
14
becomes slow. As a result, the light which passes through around the border between the attenuated layer
14
and the substrate
12
is setoff by the phase difference. Therefore, the resolution can be improved.
However, it is difficult to control a thickness and a quality of the attenuated layer. As the attenuated layer is formed on the substrate by a vacuum evaporation method, the thickness and the quality of the attenuated layer are easily influenced by the changes of the process environments or conditions. Therefore, a required transmittance and phase difference of the mask cannot be obtained. Further, once the attenuated phase-shift mask having an unsatisfied attenuated layer is formed, a required transmittance and phase difference of the mask cannot be modified by additional evaporation processes.
SUMMARY OF THE INVENTION
An objective of the invention is to resolve the above-described problem and to provide a method for correcting characteristics such as a transmittance and a phase difference, of an attenuated phase-shift mask.
The objective is achieved by a method for correcting characteristics of an attenuated phase-shift mask having an attenuated layer including (a) storing a data in a memory, which shows a correlation between characteristics and process conditions, (b) measuring the characteristics of the attenuated phase-shift mask, (c) calculating a appropriate process condition from the result of the step (b) and the data stored in the memory; and (d) soaking the attenuated phase-shift mask into a liquid solution for a certain time that is calculated in the step (c) to change thickness and composition of the attenuated layer.
REFERENCES:
patent: 5032217 (1991-07-01), Tanaka
patent: 5789118 (1998-08-01), Liu et al.
patent: 5942356 (1999-08-01), Mitsui et al.
patent: 6037083 (2000-03-01), Mitsui
patent: 6123865 (2000-09-01), Lin et al.
patent: 6242138 (2001-06-01), Mitsui et al.
Gulakowski Randy
Mimura Junichi
Oki Electric Industry Co. Ltd.
Smetana Jiri F
LandOfFree
Method for correcting characteristics of attenuated... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for correcting characteristics of attenuated..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for correcting characteristics of attenuated... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3054012