Radiation imagery chemistry: process – composition – or product th – Including control feature responsive to a test or measurement
Reexamination Certificate
2002-06-21
2004-03-30
Young, Christopher G. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Including control feature responsive to a test or measurement
C430S005000
Reexamination Certificate
active
06713219
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to a substrate exposure apparatus and method, and more particularly, to a substrate exposure apparatus and method that does not require a photomask for transferring a pattern to the photoresist.
2. Description of the Related Art
Photolithography process is one of the crucial steps in the print circuit board, the substrate and the semiconductor fabrication process. In wafer fabrication, the patterned and doped regions for each thin film layer are determined by photolithography process. Additionally, the formation of metal film patterns in the print circuit board and the substrate are determined by the photolithographic process. For each one, the photomask must be well prepared. In the photolithographic process, after some preparation procedures, the photomask is coated on the substrate, and then a soft baking and a hard baking processes are further performed. After the photoresist on the wafer is cured, the steps of exposure and development are performed to transfer the pattern of the photomask to the photoresist.
Referring to
FIG. 1
, a conventional photolithography process that uses a contact mode photomask to transfer the pattern to the photoresist is schematically shown. A substrate
100
, on which circuit, dielectric layer, dielectric pattern or conductive layer may have been formed, is provided. A photoresist
102
is formed on the substrate
100
. A photomask
110
is disposed on the photoresist
102
. To protect the surface of the photomask
110
, a protect film
104
is placed between and separates the photomask
110
and the photoresist
102
. The protect film
104
is in contact with both the surface of the photomask
110
and the photoresist
102
. By radiation of a light source
112
, an exposure step is performed on the photoresist
102
, so that the pattern of the photomask
110
is transferred to the photoresist
102
.
The conventional contact mode photomask
110
includes formation of a patterned blocking layer
108
on a surface of a transparent substrate
106
. To protect the photomask
110
, the protect film
104
sandwiched between the photomask substrate
106
and the photoresist
102
is in contact with both surfaces of the photomask substrate
106
and the photoresist
102
. The patterned blocking layer
108
of the photomask
110
blocks the light source
112
to determine the pattern on the photoresist
102
to be radiated.
Referring to
FIG. 2
, a conventional photolithography process using a non-contact mode photomask to transfer a pattern to a photoresist is schematically shown. A substrate
200
on which a photoresist
202
is formed is provided. Circuits, dielectric layers, dielectric patterns or conductive layers may have been formed on the substrate
200
. A photomask
210
is located above the photoresist
202
. A lens set
214
is disposed between the photomask
210
and the photoresist
202
. By radiation of a light source
212
, the photoresist
202
is exposed, and the pattern of the blocking layer
208
on the photomask
210
is transferred as the pattern
216
on the photoresist
202
.
The conventional non-contact mode photomask is constructed by forming the patterned blocking layer
208
on a transparent substrate
206
. The patterned blocking layer
208
on the transparent substrate
206
blocks the light source to determine the pattern of the photoresist
202
to be radiated. In a non-contact mode, the pattern of the photomask
210
is transferred to the photoresist
202
by the lens set
214
. The fabrication of the conventional photomask is very time consuming and costly. The photomask has to be kept in an appropriate environment, and the maintenance cost is also high.
In addition, the pattern of the photomask cannot be modified. When the circuit design of the wafer or printed circuit board requires a modification, a new photomask has to be fabricated.
SUMMARY OF THE INVENTION
The present invention provides a substrate exposure apparatus and method that does not require a photomask. The fabrication cost and maintenance cost of a photomask in the photolithography process are thus saved.
The substrate exposure apparatus provided by the present invention comprises a scan light source and a control system. The scan light source is located over the photoresist to be exposed on the substrate. The control system controls the scan light source or the substrate to shift along a scan path, and converts the pattern to be formed on the photoresist into a timing signal, so as to control the light and dark status of the scan light source at different times.
In the above substrate exposure apparatus, the scan light comprises multiple point light sources. The point light sources are arranged in a single file such as a line light source. Alternatively, the point light sources can be arranged in multiple files such as multiple line light sources. The line light sources are parallel to each other. Along the aligning direction of each line light source, there is a specific position shift for each of the line light sources, so that the point light sources in one line light source are staggered with the point light sources in another line light source. As a result, the exposure resolution is enhanced. The above point light sources include light emitting diodes and laser diodes.
In the substrate exposure apparatus of the present invention, the light of the scan light source is adjusted by a lens set to radiate the photoresist for exposure.
In the present invention, a substrate exposure method is provided. The substrate exposure method uses a scan light source and a control system to perform exposure on a photoresist on a substrate. The scan light source is located above the photoresist. The control system controls the scan light source or the substrate to shift along a scan path. The pattern to be transferred to the photoresist is converted into a timing signal to control the light and dark status of the scan light source, so as to perform exposure on the photoresist.
In the above substrate exposure method, the scan path of the scan light source is vertical to the aligning direction of the point light sources.
In the above substrate exposure method, the scan path of the scan light does not have to be vertical to the aligning direction of the point light sources.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
REFERENCES:
patent: 6291110 (2001-09-01), Cooper et al.
patent: 6544698 (2003-04-01), Fries
patent: 2002/0192569 (2002-12-01), Ulland et al.
patent: 2003/0084422 (2003-05-01), Chan
Jiang Chyun IP Office
Via Technologies Inc.
Young Christopher G.
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