Method of a floating pattern loading system in mask dry-etching critical dimension control

A method for the creation of a pattern of opaque material over the substrate of a photolithographic exposure mask, comprising:

• providing a CD performance criteria;
• accessing a product pattern to be created in an opaque layer of an exposure mask;
• determining a surface area of the product pattern;
• determining, based in the accessed product pattern, a Cr loading factor over the substrate of the photolithographic exposure mask;
• accessing an etch recipe of the opaque layer of an exposure mask, the etch recipe meeting Critical Diameter (CD) performance criteria for the determined Cr loading factor, this etch recipe being valid for the calculated Cr loading factor or for a Cr loading factor that is within determined limits of the Cr loading factor;
• if CD performance criteria is met by the accessed etch recipe, the etch of the opaque layer is performed;
• if the CD performance criteria is not met by the accessed etch recipe, dummy patterns are added in a dummy area of the mask;
• re-calculating the Cr loading factor, comprising the product pattern and the created dummy pattern;
• accessing a new etch recipe of the opaque material, the new etch recipe meeting the CD performance criteria for the re-calculated Cr load factor;
• etching, if CD performance criteria is met by the newly accessed etch recipe, the opaque material;
• and
• returning, if CD performance criteria is not met by the newly accessed etch recipe, to the preceding step of determining, based in the accessed product pattern, a Cr loading factor over the substrate of the photolithographic exposure mask.

A method for the creation of a pattern of opaque material over the substrate of a photolithographic exposure mask, comprising:

• determining several dry-etch recipes, whereby these several dry-etch recipes provide optimum CD performance for a number of different fixed pattern loading recipes such as 20%, 50% and 80%, said fixed pattern loading comprising forbidden surface areas;
• calculating total Cr etch loading for a given product;
• deriving, from the calculated total Cr etch loading a residue and useless area on the photolithographic mask;
• determining a pattern of Cr etching by calculating a loading factor X, whereby X=(Cr etching area/total mask area)*100%, whereby 0%<X<100%;
• performing, for values of X=20% and 50% and 80%, a first exposure;
• if for standard Cr etch recipes of respectively A=20%, B=50% or C=80%, if respectively values of X<20% or <50% or <80%, determine if enough dummy pattern can be provided to meet the criteria of X+Y=20% or 50% or 80%;
• if the latter criteria can be met with the dummy pattern the second exposure is performed;
• and
• separating, if the latter criteria cannot be met, the original patterns into pattern B and pattern C.

A system for creating a pattern in a layer of opaque material of a photolithographic exposure mask, comprising:

• a means for defining an etch recipe for etching a product pattern A in an opaque material over a substrate of a photolithographic exposure mask that optimally meets Critical Diameter (CD) requirements of the product pattern, said etching a product pattern comprising a photoresist exposure mask;
• a means for calculating the product pattern total Cr etch loading on the exposure mask;
• a means for defining a residual or useless surface area of the exposure mask;
• a means for, if the defined, optimum etch recipe meets the optimal Critical Diameter (CD) requirements, the exposure of the opaque material of the exposure mask is performed;
• a means for, if the defined, optimum etch recipe does not meet the optimal Critical Diameter (CD) requirements, then the Cr etch loading is modified by adding dummy patterns in unused areas of the photoresist exposure mask;
• a means for, if the addition of dummy pattern to the product pattern does not meet the Cr etch loading, then the Cr loading pattern A is separated into two parts B and C, such that pattern B meets Cr loading requirements, after which pattern B is applied to a first exposure process and pattern C is applied for a second exposure process.

A system for the creation of a pattern of opaque material over the substrate of a photolithographic exposure mask, comprising:

• a means for providing a CD performance criteria;
• a means for accessing a product pattern to be created in an opaque layer of an exposure mask;
• a means for determining a surface area of the product pattern;
• a means for determining, based in the accessed product pattern, a Cr loading factor over the substrate of the photolithographic exposure mask;
• a means for accessing an etch recipe of the opaque layer of an exposure mask, the etch recipe meeting Critical Diameter (CD) performance criteria for the determined Cr loading factor, this etch recipe being valid for the calculated Cr loading factor or for a Cr loading factor that is within determined limits of the Cr loading factor;
• a means for, if CD performance criteria is met by the accessed etch recipe, the etch of the opaque layer is performed;
• a means for, if the CD performance criteria is not met by the accessed etch recipe, dummy patterns are added in a dummy area of the mask;
• a means for re-calculating the Cr loading factor, comprising the product pattern and the created dummy pattern;
• a means for accessing a new etch recipe of the opaque material, the new etch recipe meeting the CD performance criteria for the re-calculated Cr load factor;
• a means for etching, if CD performance criteria is met by the newly accessed etch recipe, the opaque material;
• and
• a means for returning, if CD performance criteria is not met by the newly accessed etch recipe, to the preceding step of determining, based in the accessed product pattern, a Cr loading factor over the substrate of the photolithographic exposure mask.

A system for the creation of a pattern of opaque material over the substrate of a photolithographic exposure mask, comprising:

• a means for determining several dry-etch recipes, whereby these several dry-etch recipes provide optimum CD performance for a number of different fixed pattern loading recipes such as 20%, 50% and 80%, said fixed pattern loading comprising forbidden surface areas;
• a means for calculating total Cr etch loading for a given product;
• a means for deriving, from the calculated total Cr etch loading, a residue and useless area on the photolithographic mask;
• a means for determining a pattern of Cr etching by calculating a loading factor X, whereby X=(Cr etching area/total mask area)*100%, whereby 0%<X<100%;
• a means for performing, for values of X=20% and 50% and 80%, a first exposure;
• a means for, if for standard Cr etch recipes of respectively A=20%, B=50% or C=80% respectively values of X<20% or <50% or <80% are obtained, determining if enough dummy pattern can be provided to meet the criteria of X+Y=20% or 50% or 80%;
• a means for, if the latter criteria can be met with the dummy pattern, performing a second exposure;
• and
• a means for separating, if the latter criteria cannot be met, the original patterns into pattern B and pattern C.