Patent US5923563A successfully refreshed from Google Patents.
US5923563A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable density fill shape generation
Assignee: International Business Machines Corp
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Filing: 1996-12-20
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Granted: 1999-07-13
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Expires: 2016-12-20
Abstract
Abstract The present invention is directed to a method for adding fill shapes to a chip in a manner which accommodates a wide range of within-chip pattern density variations and provides a tight pattern density control (i) within a chip and (ii) from chip to chip. The present invention imposes a grid over a chip design pattern, wherein each section of the grid contains a portion of the chip design. A pattern density is then determined for each section of the grid, based on that portion of the chip design pattern which lies within the particular grid section. The results of the pattern density determination are used to determine where to place fill shapes in the chip design in order to increase a density value in each section of the grid to that of a target density value. The method and apparatus of the present invention provide a best fit approximation to the desired pattern density consistent with a set of layout rules for the level being patterned.
Inventors
- 👤 Mark A. Lavin
- 👤 William C. Leipold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:46
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/39; G06F30/398; G06F2119/00; G06F2119/18; Y; Y02; Y02P; Y02P90/00; Y02P90/02
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
128 words
A method of controlling a fabrication level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said method comprising the steps of: imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 2
Independent Claim
128 words
A method of controlling a fabrication level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said method comprising the steps of: imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 3
Dependent Claim
65 words
A method according to claim 1 wherein said step of establishing an actual pattern density value for each grid section comprises the steps of: determining the percentage area of each grid section which is covered with designed shapes; and assigning an actual pattern density value to each grid section based on the percentage area of each grid section which is covered with the designed shapes.
Claim 4
Dependent Claim
53 words
A method according to claim 1, wherein said step of generating a plurality of dummy fill shapes comprises the steps of: determining an available fill area for each grid section; calculating a fill pattern for each grid section; and placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 5
Dependent Claim
82 words
A method according to claim 3, wherein said step of determining the available fill area for each grid section comprises the steps of: for each of one or more levels of a grid section, generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and calculating the available fill area by complementing the areas-not-to-fill.
Claim 6
Dependent Claim
99 words
A method according to claim 3, wherein said step of calculating a fill pattern for each grid section comprises the steps of: calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; calculating a difference between the actual pattern density value of the grid section and the overall target density value; calculating a fill fraction by multiplying the fill ratio by the difference; and using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 7
Dependent Claim
53 words
A method according to claim 2, wherein said step of generating a plurality of dummy fill shapes comprises the steps of: determining an available fill area for each grid section; calculating a fill pattern for each grid section; and placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 8
Dependent Claim
82 words
A method according to claim 6, wherein said step of determining the available fill area for each grid section comprises the steps of: for each of one or more levels of a grid section, generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and calculating the available fill area by complementing the areas-not-to-fill.
Claim 9
Dependent Claim
99 words
A method according to claim 6, wherein said step of calculating a fill pattern for each grid section comprises the steps of: calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; calculating the difference between the actual pattern density value of a grid section and the overall target density value; calculating a fill fraction by multiplying the fill ratio by the difference; and using the fill fraction to access a fill table, wherein said fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 10
Dependent Claim
99 words
A method according to claim 4, wherein said step of calculating a fill pattern for each grid section comprises the steps of: calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; calculating a difference between the actual pattern density value of a grid section and the overall target density value; calculating a fill fraction by multiplying the fill ratio by the difference; and using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 11
Independent Claim
133 words
A system for controlling the fabrication of a level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said system comprising: means for imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; means for establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and means for generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 12
Independent Claim
133 words
A system for controlling the fabrication of a level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said system comprising: means for imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; means for establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and means for generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 13
Dependent Claim
66 words
A system according to claim 10 wherein said means for establishing an actual pattern density value for each grid section comprises: means for determining the percentage area of each grid section which is covered with designed shapes; and means for assigning an actual pattern density value to each grid section based on the percentage area of each grid section which is covered with the designed shapes.
Claim 14
Dependent Claim
56 words
A system according to claim 10, wherein said means for generating a plurality of dummy fill shapes comprises: means for determining an available fill area for each grid section; means for calculating a fill pattern for each grid section; and means for placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 15
Dependent Claim
85 words
A system according to claim 12, wherein said means for determining the available fill area for each grid section comprises: for each of one or more levels of a grid section, means for generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; means for calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and means for calculating the available fill area by complementing the areas-not-to-fill.
Claim 16
Dependent Claim
104 words
A system according to claim 12, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating a difference between the actual pattern density value of the grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 17
Dependent Claim
56 words
A system according to claim 11, wherein said means for generating a plurality of dummy fill shapes comprises: means for determining an available fill area for each grid section; means for calculating a fill pattern for each grid section; and means for placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 18
Dependent Claim
85 words
A system according to claim 15, wherein said means for determining the available fill area for each grid section comprises: for each of one or more levels of a grid section, means for generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; means for calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and means for calculating the available fill area by complementing the areas-not-to-fill.
Claim 19
Dependent Claim
104 words
A system according to claim 15, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating the difference between the actual pattern density value of a grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein said fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 20
Dependent Claim
104 words
A system according to claim 13, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating a difference between the actual pattern density value of a grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 21
Dependent Claim
135 words
A computer-readable medium for controlling the fabrication of a level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said computer-readable medium comprising: means for imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; means for establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and means for generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 22
Dependent Claim
135 words
A computer-readable medium for controlling the fabrication of a level in a fabrication process for producing an integrated circuit chip having an overall target density value, the fabrication level proceeding according to a design pattern, said computer-readable medium comprising: means for imposing a grid over the design pattern, the grid having a plurality of grid sections, each grid section having a portion of the design pattern contained therein; means for establishing an actual pattern density value for each grid section based upon a portion of the design pattern contained therein; and means for generating one or more dummy fill shapes in each grid section based upon the actual pattern density value in each grid section in order to obtain a resultant density value in each section on the order of the overall target density value.
Claim 23
Dependent Claim
67 words
A computer-readable medium according to claim 19 wherein said means for establishing an actual pattern density value for each grid section comprises: means for determining the percentage area of each grid section which is covered with designed shapes; and means for assigning an actual pattern density value to each grid section based on the percentage area of each grid section which is covered with the designed shapes.
Claim 24
Dependent Claim
57 words
A computer-readable medium according to claim 19, wherein said means for generating a plurality of dummy fill shapes comprises: means for determining an available fill area for each grid section; means for calculating a fill pattern for each grid section; and means for placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 25
Dependent Claim
86 words
A computer-readable medium according to claim 21, wherein said means for determining the available fill area for each grid section comprises: for each of one or more levels of a grid section, means for generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; means for calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and means for calculating the available fill area by complementing the areas-not-to-fill.
Claim 26
Dependent Claim
105 words
A computer-readable medium according to claim 21, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating a difference between the actual pattern density value of the grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 27
Dependent Claim
57 words
A computer-readable medium according to claim 20, wherein said means for generating a plurality of dummy fill shapes comprises: means for determining an available fill area for each grid section; means for calculating a fill pattern for each grid section; and means for placing fill shapes in accordance with the calculated fill pattern in each grid section.
Claim 28
Dependent Claim
86 words
A computer-readable medium according to claim 24, wherein said means for determining the available fill area for each grid section comprises: for each of one or more levels of a grid section, means for generating an area-not-to-fill, wherein the area-not-to-fill comprises the area of the grid section containing designed shapes and guardbands around the designed shapes; means for calculating an areas-not-to-fill as a union of generated area-not-to-fill for all levels of the grid section; and means for calculating the available fill area by complementing the areas-not-to-fill.
Claim 29
Dependent Claim
105 words
A computer-readable medium according to claim 24, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating the difference between the actual pattern density value of a grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein said fill table contains a corresponding fill pattern for each possible fill fraction.
Claim 30
Dependent Claim
105 words
A computer-readable medium according to claim 22, wherein said means for calculating a fill pattern for each grid section comprises: means for calculating a fill ratio by dividing the total area of a grid section by the available fill area of the grid section; means for calculating a difference between the actual pattern density value of a grid section and the overall target density value; means for calculating a fill fraction by multiplying the fill ratio by the difference; and means for using the fill fraction to access a fill table, wherein the fill table contains a corresponding fill pattern for each possible fill fraction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-07-12 | 2003-01-11 | 2003-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-07-12 | 2007-01-11 | 2007-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-07-12 | 2011-01-11 | 2011-07-13 | $7700.00 | Window Closed / Lapsed |