Computer-aided design and analysis of circuits and semiconductor – Nanotechnology related integrated circuit design
Reexamination Certificate
1998-03-13
2001-05-22
Smith, Matthew (Department: 2825)
Computer-aided design and analysis of circuits and semiconductor
Nanotechnology related integrated circuit design
C716S030000, C716S030000
Reexamination Certificate
active
06237133
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a semiconductor integrated circuit mask pattern data creation method, and more particularly to a mask pattern creation method and system that are not subject to data stream data format limitations.
BACKGROUND OF THE INVENTION
A conventional mask pattern creation method is described with reference to FIG.
8
. In the conventional system, mask pattern data created by a mask pattern data creation system
801
is converted to a stream data format, such as GDS (ECMA-96), and is output on a recording medium such as a magnetic tape as stream data
605
. Created mask pattern data is used in subsequent steps.
The mask pattern data creation system
801
has a display unit
606
such as a CRT display and a keyboard
607
for I/O processing (user interface).
FIGS. 10 and 11
schematically show the hierarchical structure of mask pattern data. An earlier patent disclosure dealing with the block layout of a hierarchical data structure having a block, sub-blocks of the block, and basic cells which are the lowest-level blocks, etc. is found, for example, in Japanese Patent Kokai Publication JP-A-61-45364.
If there is a limit that the layout angle of layout cell data
1002
which is placed in a lower hierarchical level in the stream data format must be in 90-degree units when creating hierarchically-structured mask pattern data
1001
as shown in
FIGS. 10 and 11
, a limit that a mask pattern data creation function
802
of the mask pattern creation system
801
must always create layout cell data
1002
in 90-degree units is imposed in order to avoid conflict with the limitation in the stream data format.
However, this method cannot be used to create layout cell data with an arbitrary layout angle other than 90 degrees such as 15 degrees, 30 degrees, and so forth.
On the other hand, Japanese Patent Kokai Publication JP-A-7-146945 discloses a data processing system which expands a continuous pattern in any rotational angle on a word processor or a DTP (Desk Top Publishing) system.
FIG. 9
shows the configuration of a system in which the function disclosed by Japanese Patent Kokai Publication JP-A-7-146945 is implemented in the conventional mask pattern data creation function
802
shown in FIG.
8
. Although the data processing system disclosed by the above patent publication is not a mask pattern creation system, the following describes a system in which the above-described data processing system with the function of expanding a continuous pattern of any rotational angle is applied to mask pattern data creation. The configuration of this system was invented also by the inventor of the present invention.
As shown in
FIG. 9
, the mask pattern data creation function
802
has super cell creation means
903
and expansion means (flattering means )
904
. The super cell creation means has a rotational angle storage module
902
which stores into memory angle data &thgr; (see
1301
in
FIG. 13
) entered from a keyboard
607
(see
FIG. 8
) via a control module
901
, and the super cell creation means
903
creates super cells having an arbitrary angle of &thgr; stored into memory from layout cell data (
1002
in FIGS.
10
and
11
). The expansion means (flattening means)
904
expands super cells into graphic data having no hierarchical structure (
1201
in
FIGS. 12 and 13
) onto mask pattern data. This function may create layout cell data with an arbitrary pseudo-angle of &thgr; in a hierarchical level lower than that of mask pattern data (
1001
in FIGS.
12
and
13
). Actually, the layout cell data, which is expanded graphic data
1202
(see FIGS.
12
and
13
), is in mask pattern data
1001
.
SUMMARY OF THE DISCLOSURE
Following problems have been encountered in the course of investigation toward the present invention. Namely, for mask pattern data with a hierarchical structure (see
1001
in
FIGS. 10 and 11
) described above, changes made to lower-level layout cell data (see
1002
in
FIGS. 10 and 11
) are reflected on the layout cell data. On the other hand, changes made to layout cell data with a pseudo angle of &thgr; (
1201
in FIGS.
12
and
13
), which is actually expanded graphic data, are not reflected on the layout cell data.
That is, layout cell data which is hierarchically lower than mask pattern data is rotated through an arbitrary angle of &thgr; after having been expanded into graphic data (i.e., graphic data
1201
resulting from hierarchical flattering of layout cell data). In this case, layout cell data is converted into graphic data having no hierarchical structure as shown in FIG.
12
and so it is impossible to trace layout cell data from this mask pattern data
1001
. Therefore, when a need arises to correct the original layout cell data, it must be corrected and then laid out, expanded, or rotated again.
More specifically, after manually deleting layout cell data (graphic data) with a pseudo rotation angle of &thgr; and laying out corrected layout cell data, it is necessary to create super cell data with an angle of &thgr; from the layout cell data again and to expand the super cell data into graphic data having no hierarchical structure onto the mask pattern data.
At this time, there is a possibility that the user specifies incorrect layout coordinates, rotational angle &thgr;, and layout cell data location (storage location or address).
The present invention seeks to solve the problems associated with the prior art described above. It is an object of the present invention to provide a creation method of mask pattern data having a hierarchical structure, which automatically reflects changes done to layout cell data when correcting the layout cell data hierarchically lower than mask pattern data, and eliminates the need for a user to manually perform deletion processing or layout processing in order to prevent human errors that may be introduced into layout data on the layout cell data to be laid out in mask pattern data.
It is a further object of the present invention to provide a system or program for carrying out the method.
Still further objects of the present invention will become apparent in the entire disclosure.
To achieve the above object, there is provided a mask pattern data creation method according to a first aspect of the present invention. The method comprises the steps of placing layout cell data hierarchically below dummy cell data based on entered layout data of the layout cell data, placing the dummy cell data hierarchically below mask pattern data, and on the other hand adding the layout data of the layout cell data to the dummy cell data as additional data; and creating graphic data rotated through an angle specified in the layout data by expanding the layout cell data placed hierarchically below the dummy cell data.
According a second aspect, there is provided a mask pattern data creation system. The system comprises layout data input means which reads layout data of layout cell data; dummy cell layout means which places the layout cell data hierarchically below dummy cell based on said layout data and places said dummy cell data hierarchically below mask pattern data, and which adds the layout data of said layout cell data to said dummy cell data as additional data. The system further comprises layout expansion means which creates graphic data corresponding to an angle specified in the layout data by expanding the layout cell data placed hierarchically below said dummy cell data.
The mask pattern data creation system may further comprises layout data acquisition means which reads the layout data from said dummy cell data when the layout cell data is corrected; and deletion means which deletes the graphic data from said dummy cell data.
The mask pattern data creation system may preferably comprises layout data acquisition means which gets the layout data of the layout cell data not satisfying a format limitation upon outputting the mask pattern data.
According to a third aspect of the present invention, there is provided a computer-readable medium having stored therein a mask pattern cr
NEC Corporation
Siek Vuthe
Smith Matthew
Sughrue Mion Zinn Macpeak & Seas, PLLC
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