Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Reexamination Certificate
2000-06-28
2004-09-07
Lee, John R. (Department: 2881)
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
C430S030000, C430S296000, C382S144000, C382S145000, C250S492100
Reexamination Certificate
active
06787784
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a charged-particle beam drawing method for drawing the pattern of a semiconductor integrated circuit such as an LSI on a sample such as a mask or wafer at high speed and high precision and, more particularly, to a data creation method for realizing high-precision drawing using drawing pattern data prepared by compressing data, and a charged-particle beam drawing apparatus using the same.
BACKGROUND OF THE INVENTION
In recent years, LSI patterns continue to shrink in feature size and increase in integration degree. For example, the integration degree of DRAMs is increasing from 64 M to 256 M, 1 G, and 4 G. The micropatterning technique is one of the most important process techniques.
An electron beam drawing apparatus, which can perform micropatterning at 0.1 &mgr;m or less, is expected as an effective exposure means for forming a highly integrated LSI pattern. In drawing a desired LSI pattern using this electron beam drawing apparatus, design pattern data created by a pattern data creation tool such as a CAD used for LSI pattern design cannot be directly supplied as drawing pattern data for the electron beam drawing apparatus. For this reason, design pattern data must be converted into a data system receivable by the electron beam drawing apparatus so as to draw the data at a high speed.
An example of the electron beam drawing apparatus will be described.
FIG. 9
shows the data flow (prior art) of a drawing system. In the data conversion step, design pattern data
51
stored in an external storage device such as a magnetic disk is read in the memory of a computer in data read (step
50
). In data processing (step
52
), a multiple-exposed region is removed, and correction processing such as proximity effect correction is done. Then, basic figure division (step
53
) into a rectangle, trapezoid, triangle, and the like is executed for each unit drawing region determined by a beam deflection region. Accordingly, the design pattern data
51
is converted into drawing pattern data
55
receivable by the electron beam drawing apparatus.
In drawing data storage (step
54
), the converted drawing pattern data
55
is stored in an external storage device represented by a magnetic disk.
In the data transfer step, the drawing pattern data
55
converted in the previous step is read in step
56
, transferred to a buffer memory in step
57
, and registered in step
58
. Then, the data transfer step is complete.
In the drawing step, JOB data
61
serving as drawing schedule data of the electron beam apparatus is read in drawing condition setting (step
60
). In stripe data read (step
62
), drawing pattern data of one stripe to be drawn by one stage scanning is read out from the buffer memory in step
58
. The drawing pattern data made up of basic figures undergoes bitmapping processing (step
63
). The bitmap data is transferred to a pattern memory in step
64
, and output to a beam blanker serving as a beam-ON/OFF means in step
65
. Then, an electron beams is ON/OFF-controlled to draw a pattern (step
66
). After one stripe is drawn, the drawing step restarts from stripe data read (step
62
) for drawing the next stripe. This is repeated to complete drawing of all chips placed on a wafer.
FIG. 10
is a block diagram showing an electron beam drawing apparatus for drawing a pattern in accordance with data flow (prior art) of the above drawing system. The electron beam drawing apparatus is roughly constituted by an electron beam drawing apparatus main body
280
and a drawing control system
290
. The electron beam drawing apparatus main body
280
is comprised of an electron gun
201
, convergent lens
202
, reduction lens
203
, deflector
204
, blanker
205
, and stage
207
. An electron beam EB emitted by the electron gun
201
is converged into 0.1 &mgr;m or less via the convergent lens
202
and reduction lens
203
to irradiate a wafer
208
on the stage. The electron beam EB is adjusted in position by the deflector
204
(made up of two, a main deflector
204
-
1
and a sub-deflector
204
-
2
), and ON/OFF-controlled by the blanker
205
.
An electron beam EB emitted by the electron gun
201
is converged into 0.1 &mgr;m or less via the convergent lens
202
and reduction lens
203
to irradiate a wafer
208
on the stage. The electron beam EB is adjusted in position by the deflector
204
(made up of two, main deflector
204
-
1
and sub-deflector
204
-
2
), and ON/OFF-controlled by the blanker
205
.
In the drawing control system
290
, drawing pattern data
224
stored in an external storage device
210
such as a magnetic disk is transferred via a CPU
212
to an internal buffer memory
214
of a drawing data processing unit
219
on the basis of settings from a console
211
. The data format of the drawing pattern data
224
is a basic figure such as a rectangle, trapezoid, triangle, or the like, which is obtained by dividing design pattern data into figures. The drawing pattern data
224
is subjected in figure calculation processing
217
to calculation processing of converting data of one stripe to be drawn by one stage scanning into bitmap data. Then, the bitmap data is transferred to a pattern memory
218
.
After the bitmap data is transferred to a blanker control unit
220
, the electron beam EB is ON/OFF-controlled. In synchronism with this, a deflector control unit
222
settles the beam position, and a stage control unit
223
controls the stage position. A series of drawing operations is performed.
FIGS. 11A
to
11
C show a drawing method when the deflector
204
shown in
FIG. 10
is made up of the two, main deflector
204
-
1
and sub-deflector
204
-
2
. The stage reciprocally scans in a direction (X) perpendicular to the beam deflection direction (Y) of the electron beam EB by the main deflector
204
-
1
, thereby drawing a pattern on all the regions of chips
251
arrayed on the wafer
208
. Within the region of a main field
252
scanned by the main deflector
204
-
1
, the sub-deflector
204
-
2
deflects the electron beam EB to draw a pattern in the region of a smaller subfield
254
. The region where the electron beam EB is deflected in the subfield
254
is defined as a basic drawing region, which is reflected on data of basic figure division in creating drawing pattern data from design pattern data in the data conversion step.
As described above, in the conventional electron beam drawing apparatus, design pattern data is defined by a figure system comprised of receivable basic figures (rectangle, trapezoid, triangle, and the like). Further, the design pattern data is defined by a data system obtained by region division for each unit drawing region which depends on the drawing method of the electron beam drawing apparatus. In this manner, drawing pattern data is created to draw a pattern.
However, this method suffers the following problem.
More specifically, when sorting processing (data rearrangement processing in the drawing order) is executed in units of basic drawing regions while design pattern data created by the CAD is converted into drawing pattern data, the repetitive periodic structure of the pattern of the design pattern data becomes different in size from the unit drawing region of the electron beam drawing apparatus, and becomes different in size from the main field. If the design pattern data is simply divided in units of unit drawing regions/main field regions, the repetitive periodic structure is inhibited. The data must be mapped into many independent divided patterns, which makes it difficult to compress drawing pattern data. For this reason, the pattern regularity defined by the design pattern data is destroyed to increase the data amount and prolong the data conversion time.
Also, in the data transfer step before the start of drawing, a time required to transfer drawing pattern data obtained by data conversion from an external storage device represented by a magnetic disk to a buffer memory unit is prolonged. In the drawing step, a long time is spent on bitmapping drawing pattern
Canon Kabushiki Kaisha
El-Shammaa Mary
Fitzpatrick ,Cella, Harper & Scinto
LandOfFree
Charged-particle beam drawing data creation method, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Charged-particle beam drawing data creation method, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Charged-particle beam drawing data creation method, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3204948