Computer-aided design and analysis of circuits and semiconductor – Nanotechnology related integrated circuit design
Reexamination Certificate
1999-10-06
2002-09-10
Niebling, John F. (Department: 2812)
Computer-aided design and analysis of circuits and semiconductor
Nanotechnology related integrated circuit design
Reexamination Certificate
active
06449758
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for and a method of automatically placing and routing, which automatically generates pattern data for a mask that is used in the photolithography process when manufacturing a semiconductor integrated circuit device.
BACKGROUND OF THE INVENTION
As part of the manufacturing process for manufacturing a semiconductor integrated circuit device, there is a photolithography process in which a photosensitive resist having been coated onto the surface of a semiconductor wafer is exposed, via a mask having a desired mask pattern drawn therein, and then the resist is developed to form a resist mask. FIG.
8
and
FIG. 9
each are a longitudinal sectional view illustrating how a metal distribution of a semiconductor integrated circuit apparatus is formed in the photolithography process. As illustrated in
FIG. 8
, for example, when forming a metal distribution, a metal distribution layer
13
is laminated via a layer insulation film
12
on a semiconductor wafer in which transistor etc. has been formed. Then, a resist film
14
is laminated on the surface of this metal distribution layer
13
. Then, the resist film
14
is exposed using a mask
15
on which a distribution pattern has been drawn.
The resulting structure is developed as explained in FIG.
9
. The exposed portion of the resist film is dissolved to thereby cause the non-exposed portion to remain as is. By performing etching treatment by using this remaining portion
16
as a mask, a metal distribution having a desired pattern is formed in the metal distribution layer
13
. When the mask pattern is fine, the pattern width W
2
of the actually obtained remaining resist portion
16
becomes inconveniently small in width compared to the pattern width W
1
as initially designed due to the light proximity effect. Accordingly, the line width of the metal distribution that is obtained after performance of the etching treatment also becomes inconveniently narrower than the initially designed value.
FIG. 10
is a typical view illustrating part of a layout pattern that has been prepared using an automatic placing and routing apparatus. In the figure, the reference numeral
21
denotes a standard cell, and the reference numeral
22
denotes a distribution between the standard cells
21
. The above-described narrowing of the distribution width due to the light proximity effect occurs at an end
22
a
(FIG.
11
), or a bend
22
b
(
FIG. 12
) of the distribution
22
. Namely, the line width of the end
22
a
or the bend
22
b
of the distribution
22
inconveniently becomes narrower than the originally designed value (the left side views in FIG.
11
and FIG.
12
).
To account this, conventionally, as illustrated in
FIG. 13
, with respect to the end
22
a
or bend
22
b
of the distribution
22
, preparation is made of data (hereinafter called “additional distribution data”) for providing additional distribution portions
23
a
,
23
b
for correcting the portion of the distribution where possibly the distribution width inconveniently becomes narrower in an actual process. These additional distribution portions
23
a
,
23
b
are generated using a layout verifying apparatus, after having prepared cell-assignment-pattern data and distribution-pattern data by using the automatic placing and routing apparatus.
FIG. 14
is a functional block diagram illustrating a conventional system for preparing the additional distribution data in accordance with the additional-distribution-data preparing procedure. With reference to this figure, the construction of this system will now be explained along with the additional-distribution-data preparing procedure. First, arrangement data and wire distribution data are prepared by the automatic placing and routing apparatus
31
to obtain source layout data
32
. This source layout data
32
does not include the above-described additional distribution data.
Subsequently, using the source layout data
32
and a layout-verifying rule file
34
for generating additional distribution data, verification of the layout is performed by a layout verifying apparatus
33
to thereby obtain additional distribution data production information
35
. According to the additional distribution data production information
35
and the source layout data
32
, corrected layout data
36
containing the additional distribution data therein is obtained. And, using the corrected layout data
36
and a rule file
37
for verifying the layout data as a whole, verification of the layout is performed again by the layout verifying apparatus
33
, thereby obtaining final pattern data
38
for use on a mask. This pattern data
38
for use on a mask includes the additional distribution data.
However, in the above-described conventional additional distribution data preparation method, a significantly longer time is needed for obtaining the final pattern data for use on a mask that includes the additional distribution data therein, so that the efficiency is disadvantageously poor.
SUMMARY OF THE INVENTION
The present invention has been made in order to solve the above-described problem and an object of the invention is to provide an apparatus for and a method of automatically placing and routing which, in a state of designing the mask used to manufacture a semiconductor integrated circuit device, makes it possible to quickly obtain final pattern data containing additional distribution data therein.
According to this invention, the cell assigning section automatically performs assignment of the cells according to the circuit data, the distribution path determining section automatically determines the distribution path between the cells that have been assigned, the distribution information extracting section extracts the information regarding the distribution path that has been determined, the prescribed-information recognizing section recognizes the information of a prescribed portion of the distribution according to information that has been extracted, the additional-distribution-data generating section generates the additional distribution data for correcting the width of distribution of the prescribed portion of the distribution that has been recognized, and the additional-distribution-data lay-out section lays out the additional distribution data that has been generated with respect to the prescribed portion of the distribution.
In this invention, the prescribed portion of the distribution may be an end or a bend of the distribution. With such a configuration, the prescribed-information recognizing section recognizes the information of the end or the bend as the prescribed portion of the distribution, the additional-distribution-data generating section generates the additional distribution data for correcting the width of distribution of the end or the bend of the distribution that has been recognized, and the additional-distribution-data lay-out section lays out the additional distribution data that has been generated with respect to the end or the bend of the distribution.
Further, a construction may be made wherein the additional-distribution-data lay-out section imparts a layer number different from that of the prescribed portion of the distribution to additional distribution data corresponding to this prescribed portion. With this configuration, the layer number of the prescribed portion of the distribution and the layer number of the additional distribution data corresponding to this prescribed portion become different from each other.
Further, a construction may be made wherein the additional-distribution-data generating section generates additional distribution data in such a way that a different size of additional distribution is laid out when the prescribed portion of the distribution is an end and when this prescribed portion is a bend. With this configuration, there is generated additional distribution data in such a way that a different size of additional distribution is laid out between when the prescribed portion of the distribution is an end and when this
Nakai Ryo
Satoh Takao
Burns Doane , Swecker, Mathis LLP
Mitsubishi Denki & Kabushiki Kaisha
Niebling John F.
Whitmore Stacy
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