WO2005104193A1 - 電子ビーム露光データ補正方法 - Google Patents
電子ビーム露光データ補正方法 Download PDFInfo
- Publication number
- WO2005104193A1 WO2005104193A1 PCT/JP2004/004513 JP2004004513W WO2005104193A1 WO 2005104193 A1 WO2005104193 A1 WO 2005104193A1 JP 2004004513 W JP2004004513 W JP 2004004513W WO 2005104193 A1 WO2005104193 A1 WO 2005104193A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pattern
- electron beam
- beam exposure
- exposure data
- correction
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/317—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation
- H01J37/3174—Particle-beam lithography, e.g. electron beam lithography
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/302—Controlling tubes by external information, e.g. programme control
- H01J37/3023—Programme control
- H01J37/3026—Patterning strategy
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/36—Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/30—Electron or ion beam tubes for processing objects
- H01J2237/317—Processing objects on a microscale
- H01J2237/3175—Lithography
- H01J2237/31769—Proximity effect correction
Definitions
- the present invention relates to electron beam exposure, and more particularly to correction of electron beam exposure data.
- the method of manufacturing a semiconductor device includes steps of exposure, development, and etching.
- the resist is irradiated with ultraviolet rays or an electron beam.
- a resist having a predetermined pattern is formed.
- the resist pattern after development is distorted as compared with the exposure pattern. Therefore, proximity effect correction is performed.
- Proximity effect correction can prevent deformation of the resist pattern due to the influence of other exposure areas by correcting the pattern shape of the mask when exposing a resist in a fine area.
- Patent Document 1 listed below describes a proximity effect capturing method.
- Patent Document 2 below describes a proximity effect correction method when performing electron beam transfer exposure on a substrate on which an underlayer is formed.
- Patent Document 3 describes a method for detecting a proximity effect that occurs depending on the surrounding state of a pattern.
- Patent Document 4 below discloses that the exposure amount of an electron beam is different between a central portion and a peripheral portion of a pattern.
- Patent Document 1 Japanese Patent Application Laid-Open No. H10-09087
- Patent document 2 Japanese Patent Application Laid-Open No. H11-13554424
- Patent Document 3 Japanese Patent Application Laid-Open No. 2000-212672
- Patent Document 4 Japanese Patent Application Laid-Open No. 9-29841
- an electronic device that can be identified for each pattern type of a semiconductor device.
- An electron beam exposure data correction method is provided.
- the first type of pattern is, for example, a dummy pattern that does not affect the function of the semiconductor device, and does not necessarily require correction.
- the second type of pattern is a normal pattern that affects the function of the semiconductor device, for example, and requires correction. Maintain the function of the semiconductor device by dividing into the first type of pattern that does not require correction and the second type of pattern that requires correction, and performing correction on only the second type of pattern.
- the generation time and / or exposure time of the electronic data exposure data can be reduced.
- FIG. 1 is a cross-sectional view illustrating an example of a semiconductor device manufactured using electron beam exposure data generated according to an embodiment of the present invention.
- FIG. 2A is a diagram showing variable rectangular exposure
- FIG. 2B is a diagram showing batch exposure.
- FIG. 3A is a hierarchical structure diagram of the structure
- FIG. FIG. 4 is a diagram showing a configuration example of a structure.
- FIG. 5 is a flowchart showing the electron beam exposure data processing according to the present embodiment.
- FIG. 6 is a flowchart showing details of the etching correction process.
- FIG. 7 is a diagram for explaining the structure creation processing.
- Reference numeral 8 is a flowchart showing details of the exposure data format conversion process.
- FIG. 9 is a flowchart showing details of the contour division processing.
- FIG. 10 is a diagram for explaining the pattern division processing.
- FIG. 11 is a diagram for explaining the etching process.
- FIG. 12A and FIG. 12B are diagrams for explaining the proximity effect correction processing.
- FIG. 13 is a diagram illustrating a first etching correction example.
- FIG. 14 is a diagram illustrating a second etching correction processing example.
- FIG. 15 is a diagram showing a third example of the etching correction process.
- FIG. 16 is a diagram showing the shift processing of the pattern width.
- FIG. 17 is a flowchart showing another electron beam exposure data processing.
- FIG. 18 is a block diagram illustrating an example of a hardware configuration of a computer. BEST MODE FOR CARRYING OUT THE INVENTION
- FIG. 1 is a cross-sectional view illustrating an example of a semiconductor device manufactured using electron beam exposure data generated according to an embodiment of the present invention.
- the semiconductor device has, for example, a first wiring layer 101, a via layer (insulating layer) 102, a second wiring layer 103, and the like on a silicon substrate.
- the first wiring layer 101 has patterns 111 and 112 of metal wiring such as aluminum.
- the second wiring layer 103 has patterns 131 and 132 of a metal wiring such as aluminum.
- the via layer 102 has via plugs 121 and 122 made of heavy metal such as tungsten. The above patterns are separated by insulating material.
- the via plug 1 2 1 connects the wiring patterns 1 1 1 and 1 3 1.
- the via plugs 122 connect the wiring patterns 111 and 132.
- the wiring pattern 112 is a dummy pattern that does not affect the function of the semiconductor device.
- Other patterns 1 1 1, 1 2 1, 1 2 2, 1 3 1 and 1 3 2 are normal patterns that affect the function of the semiconductor device. If there is no dummy pattern 1 12, the portion will not be flat, and adverse effects such as disconnection of the wiring pattern 13 2 thereabove will occur.
- the dummy pattern 1 1 2 is a pattern for flattening a semiconductor device.
- Manufacturing a semiconductor device includes the steps of exposure, development and etching. For example, a metal layer is formed on a silicon substrate, and a resist is applied thereon. When the resist is exposed to an electron beam in a predetermined pattern and then developed, a predetermined pattern of the resist remains. Then, the above-mentioned metal layer is etched using the above-mentioned resist as a mask, whereby a predetermined metal wiring pattern is generated.
- electron beam exposure data is generated based on design data of a pattern of each layer of a semiconductor device, and electron beam exposure is performed.
- Normal patterns 1 1 1 and 1 3 1, etc. affect the function of the semiconductor device, and therefore require high-precision alignment.
- the dummy pattern 112 does not affect the function of the semiconductor device, a high-precision alignment is unnecessary.
- Generate electron beam exposure data When the electron beam exposure data is generated for each of the normal pattern 11 1 and the like and the dummy pattern 1 12 by a high-precision alignment, the generation time and the exposure time become long.
- the generation time and the exposure time are shortened by simplifying the process of generating the electron beam exposure data of the dummy pattern 112. can do. The details are described below.
- Electron beam exposure is capable of transferring finer patterns than exposure using ultraviolet light, and is being developed as a next-generation exposure method.
- FIG. 2A shows a variable rectangular exposure
- FIG. 2B shows a batch exposure. Electron beam exposure is performed by combining variable rectangular exposure and batch exposure according to the pattern.
- an electron beam exposure apparatus 201 irradiates an electron beam 202 onto a semiconductor wafer 206 via a mask 203 according to electron beam exposure data.
- the mask 203 has one opening 204.
- the electron beam 202 is applied to the region 205 on the mask 203 and the electron beam passing through the opening 204 is applied to the region 207 on the semiconductor wafer 206.
- Variable rectangle exposure exposes patterns one by one with a variable shaped electron beam.
- an electron beam exposure apparatus 211 irradiates an electron beam 212 onto a semiconductor wafer 216 via a mask 213 according to electron beam exposure data.
- a plurality of openings 214 are provided in the block 2 15 of the mask 2 13.
- the electron beam 2 12 is applied to the block 2 15 on the mask 2 13 and the electron beam passing through the plurality of openings 2 14 is applied to the plurality of regions 2 17 on the semiconductor wafer 2 16.
- You. Batch exposure exposes a plurality of patterns at once.
- the exposure amount is set in the exposure pattern, energy corresponding to the exposure amount is stored in the register, and the pattern is developed at a location where the energy is high. That is, at the time of image development, a portion having a large exposure amount remains, and a portion having a small exposure amount is removed.
- the storage energy is the energy that is accumulated by forward scattering, in which electrons gradually spread when a resist is irradiated with an electron beam, and the energy that strikes the semiconductor substrate after passing through the resist, It is determined from the sum of the energy accumulated by the backscattering reflected to the resist. Details will be described later with reference to FIG. 12B.
- Electron beam exposure data to be input to the electron beam exposure apparatuses 201 and 211 are created from design data.
- the design data is composed of a hierarchy of structures, for example, as shown in FIGS. 3A and 3B.
- FIG. 3A is a hierarchical structure diagram of the structure, and FIG. Below the top-level structure TOP, there are four types of structures A, B, C and D. Specifically, four structures A (301 to 304) and one structure B (305) are arranged under the structure TOP. Each structure A (30 1 to 304) includes 12 structures C (306) and 4 structures D (307).
- FIG. 4 shows a configuration example of the structure C (306).
- the structure C (306) is composed of patterns 401 of each layer, and each pattern has a layer number defined.
- X and Y represent the horizontal and vertical size of the structure C, respectively.
- FIG. 5 is a flowchart showing the electron beam exposure data processing according to the present embodiment. This process is performed for each layer of the semiconductor device.
- step S501 the above design data 511 is input, and a graphic logic operation process is performed.
- a graphic logical operation processing a logical sum (OR) processing and a shift processing of the pattern width are performed on the design data 5 11 to remove the overlap between the patterns.
- step S502 an etching correction process is performed.
- the etching correction process is a correction that takes into account the difference in etching rate depending on the pattern. The details will be described later with reference to the flowchart in FIG. After that, the intermediate data 5 1 and 2 are output.
- the format of the intermediate data 5 12 is the same as the design data 5 11.
- step S503 an exposure data format conversion process is performed.
- exposure The data format conversion processing converts the format of the intermediate data 511 and outputs the exposure data 513. That is, the format of the electron beam exposure data is converted from the design data to the exposure data. The details of the process will be described later with reference to FIG.
- step S504 proximity effect correction processing is performed, and exposure data 515 is output.
- correction is performed in consideration of the amount of electrons reflected from a layer below the resist when an electron beam is irradiated on the resist. For example, when exposing the pattern of the second wiring layer 103 in FIG. 1, the amount of electrons reflected (backward scattered) from the underlying via layer 102 and the pattern of the first wiring layer 101 is exposed. Is corrected in consideration of Hereinafter, a specific example will be described with reference to FIGS. 12A and 12B.
- a pattern 1 201 is an electron beam exposure pattern.
- a pattern 1202 is a resist pattern after performing exposure and development based on the electron beam exposure pattern 1201.
- FIG. 12B is a cross-sectional view of the semiconductor device when exposing the electron beam exposure pattern 1201 of FIG. 12A.
- the electron beam exposure pattern 1 201 has a first pattern 1 211 and a second pattern 1 212.
- the gap 1 224 is an area where there is no pattern between the patterns 121 1 and 122 2.
- the pattern 1221 is a via plug pattern one layer below the layer of the first pattern 1221.
- the pattern 1 222 is a wiring pattern of a layer two layers below the layer of the first pattern 122 1.
- the pattern 1223 is a wiring pattern of a layer two layers below the layer of the second pattern 122.
- a resist 1243 is a resist for forming the patterns 1211 and 1212 of FIG. 12A.
- a via plug pattern 1221 is provided in the via layer immediately below the resist 1243.
- Wiring patterns 1222 and 1223 are provided on the wiring layer two layers below the resist 1243. They are covered with insulating material 1244.
- the electron beam 1 241 is an electron beam that has passed through a mask to form the pattern 1211 in FIG. 12A.
- the light passes through 1 243, is reflected by patterns 1221 and 1222, is backscattered, and is applied to the register 1243.
- the electron beam 1242 is an electron beam that has passed through a mask to form the pattern 1212 in FIG. 12A.
- the electron beam 1242 irradiates the resist 1243 and passes through the register 1243 to form the pattern 1223. Then, the light is reflected back, scattered and irradiates the resist 1243.
- the backscattering described above As a result of the backscattering described above, a large amount of electrons are irradiated to the area of the gap 1224 of the resist 1243, and that portion remains after development. As a result, in the resist pattern 1202 of FIG. 12A, the dimensions of the patterns 1 2 1 1 and 1 2 1 2 are enlarged and come into contact, and the patterns 1 2 1 1 and 1 2 1 2 Short-circuits. Therefore, it is necessary to determine the exposure amount of the pattern in consideration of the backscattering which reflects the electrons colliding with the layer below the resist 1243 (for example, via plugs (including contact plugs) and wiring patterns). . That is, in order to calculate the accumulated energy due to backscattering, the information of the lower layer pattern (number of patterns, pattern size, pattern arrangement position, etc.) and the correction parameter (backscattering coefficient) for the pattern are referred to.
- the exposure data for the lower layer is created by the same processing (Fig. 5) as for the layer to be processed.
- Input a control file that describes the lower layer exposure data and the backscatter coefficient for the exposure data.
- the exposure data of three layers from the layer close to the register is input, and the backscattering coefficient is described in the control file as follows.
- the stored energy is calculated, and the exposure is set so that the pattern size after development becomes the same as the pattern size in the design data.
- the stored energy is calculated mainly by the pattern density and the amount of electrons reflected on the resist, and the backscattering coefficient is defined as a coefficient representing the amount of electrons. In regions where the pattern density is high, the stored energy due to backscattering increases. Conversely, in low regions, the stored energy become smaller. Also, if the backscattering coefficient is large, the amount of reflected electrons is large. Conversely, if it is small, the amount of reflected electrons is small.
- the backscattering coefficient is determined according to the number of layers under the resist and the patterns in the layers, and the proximity effect correction is performed.
- the pattern width is shifted in the figure logical operation processing in step S501 of FIG.
- the pattern 1601 is shifted by 1 / im
- a pattern 16602 is obtained.
- the pattern width becomes large after exposure and development
- the pattern width is shifted in the negative direction.
- three layers of exposure data are input from the layer closest to the resist, and pattern shifts are performed at different sizes for each lower layer.
- the shift size for each lower layer is shown below.
- the shift size of the pattern width is determined according to the number of layers under the resist and the pattern in the layer, and the proximity effect correction is performed by shifting at the shift size.
- FIG. 6 is a flowchart showing details of the etching correction process in step S502 of FIG.
- step S601 a control file is input.
- the control file describes the layer numbers defined for the normal pattern and the dummy pattern, respectively.
- the dummy pattern is a pattern that does not affect the function of the semiconductor device
- the normal pattern is a pattern that does not affect the function of the semiconductor device.
- step S602 referring to the layer number of the control file, it is checked whether the processing target is a dummy pattern or a normal pattern. If it is a normal pattern, the process proceeds to step S603. If it is a dummy pattern, the process proceeds to step S604 without performing the etching process (S603).
- step S603 an etching correction process is performed. The details will be described later with reference to FIGS. 13 to 15. Thereafter, the process proceeds to step S604.
- step S604 it is checked whether or not processing of all patterns has been completed. If completed, proceed to step S605, otherwise complete step S602 Return to and perform the processing of the next pattern.
- a structure of output data is created. As shown in FIG. 7, a structure is created in which the entire area of the data 700 is divided into small processing areas 701.
- the processing area 701 has the area size described in the control file, and the first three characters of the structure name are, for example, "ABC".
- the structuring name of the first processing area 701 is "AB C-1”
- the structuring name of the second processing area 701 is "AB C-2”.
- the divided processing regions 701 all have the same shape. The details will be described later.
- step S606 intermediate data is output.
- the time for generating the electron beam exposure data and the time for exposure can be reduced by eliminating the unnecessary etching correction processing (S603).
- FIG. 11 is a diagram for explaining the etching correction process.
- Pattern 1 101 is a design data pattern.
- the pattern 1102 is a resist pattern after exposure and development based on the design data pattern 1101.
- the pattern 1103 is a metal wiring etched using the resist pattern 1102 as a mask. It is a pattern.
- the design data pattern 111 has a first pattern 111, a second pattern 111, and a third pattern 111. If the proximity effect correction processing is performed, no distortion occurs in the shape of the pattern 1102 after exposure and development.
- the width of the pattern 111 is set to PS1
- the width of the pattern 111 is set to PS2
- the width of the pattern 111 is set to PS3.
- the width of the pattern 1 1 1 3 is PS 6.
- the widths PS1 and PS4 are the same
- the widths PS2 and PS5 are the same
- the widths PS3 and PS6 are the same.
- the pattern 1 103 after etching The pattern width becomes smaller than the width of the design data pattern 111.
- the width of the pattern 1 1 13 is PS 9.
- the width P S7 is smaller than P S4
- the width P S9 is smaller than P S6, and the width P S8 is the same as P S5.
- the dimensions of the pattern 1103 after the etching are different from the dimensions of the design data pattern 101. Due to this phenomenon, the pattern dimension after etching falls outside the range of a predetermined standard value, and the semiconductor device cannot exhibit its expected performance. Therefore, it is necessary to perform an etching correction process.
- FIG. 13 shows a first etching correction processing example.
- the pattern 1301 is a design data pattern and includes patterns 1311, 1312 and 1313.
- the width of the pattern 1311 is PS10
- the width of the pattern 1312 is PS11
- the width of the pattern 1313 is PS12.
- the pattern 1302 is a pattern obtained by etching-correcting the design data pattern 1301.
- the width of the pattern 1311 is PS13
- the width of the pattern 1312 is PS14
- the width of the pattern 1313 is PS15. Since the etching proceeds further on the left side of the pattern 1311 and on the right side of the pattern 1313, the pattern width is increased to the left side of the pattern 1311 and to the right side of the pattern 1313.
- the width PS 13 is larger than the width PS 10 and is corrected to PS 10 + EX 1.
- the width PS 14 is the same as the width PS 11.
- the width PS15 is larger than the width PS12 and is corrected to PS12 + EX1.
- the pattern 1303 is a resist pattern that has been exposed and developed based on the pattern 1302.
- the width of the pattern 1311 is PS16, the width of the pattern 1312 is PS17, and the width of the pattern 1313 is PS18.
- Width PS16 is the same as width PS13
- width PS17 is the same as width PS14
- width PS18 is the same as width PS15.
- the pattern 1304 is a metal wiring pattern etched using the resist pattern 1303 as a mask.
- the width of the pattern 1311 is PS19, the width of the pattern 1312 is PS20, and the width of the pattern 1313 is PS21. The etching easily proceeds on the left side of the pattern 1311 and on the right side of the pattern 1313.
- the width PS 19 is smaller than width PS 16 and is the same as width PS 10.
- the width PS 20 is the same as the width PS 17.
- the width PS 21 is smaller than the width PS 18 and equal to the width PS 12.
- FIG. 14 shows a second example of the etching correction process.
- the pattern 1401 is a design data pattern, and includes a pattern 1441 and a pattern 1412.
- the width of the pattern 1 4 1 1- is PS 2 2
- the width of the pattern 1 4 1 2 is PS 2 3.
- the pattern 1442 is a pattern obtained by correcting the design data pattern 1441 by etching.
- Pattern 1 4 1 1 extends the pattern width EX 2 to the left, and pattern 1 4 1 2 extends the pattern width EX 2 to the right. Then, even on the left side of the pattern 1 4 1 2, the pattern width is extended by EX 2 to the left except for the portion facing the pattern 1 4 1 1.
- the width P S 24 of the pattern 1 4 1 1 is P S 2 2 + EX 2.
- the corrected width PS25 of the pattern 1412 is PS23 + EX2 + EX2.
- the pattern 1403 is a pattern obtained by format-converting the pattern 1442 into exposure data.
- the pattern 1412 is divided into three patterns by the exposure data format conversion process (S503 in FIG. 5).
- the width P S 26 of the pattern 14 11 is the same as the width P S 24.
- the width P S 27 of the pattern 14 12 is the same as the width P S 25.
- the pattern 1444 is a resist pattern after being exposed and developed based on the pattern 1403.
- Pattern: The width P S 28 of L 4 11 is the same as the width P S 26.
- the width P S 29 of the pattern 14 12 is the same as the width P S 27.
- the pattern 1405 is a metal wiring pattern etched using the resist pattern 1444 as a mask.
- the width PS 30 of the pattern 1411 is the same as the width PS 22.
- the width P S31 of the pattern 1412 is the same as the width P S23.
- FIG. 15 shows a third example of the etching correction process.
- the pattern 1501 is a design data pattern and includes the patterns 1511 and 1512.
- the width of the pattern 1511 is PS32, NO, and the turn 1512.
- the width is PS 33.
- the spacing between patterns 1511 and 1512 is D1.
- Pattern 1502 is a pattern obtained by correcting the design data pattern 1501 by etching. It is.
- the pattern width is extended by EX 3 on the left side of the pattern 1511 and on the right side of the pattern 1512 for the same reason as in FIGS.
- the size of the distance D1 between the pattern 1511 and the pattern 1512 is referred to.
- the width PS34 of the pattern 1511 is PS32 + EX3 + X4.
- Pattern 1 5 1 2 width? S35 is PS33 + EX3 + EX4.
- Pattern 1 503 is a resist pattern after exposure and development based on pattern 1 502.
- the width PS36 of the pattern 1511 is the same as the width PS34, and the width PS37 of the pattern 1512 is the same as the width PS35.
- Pattern 1 504 is a metal wiring pattern etched using resist pattern 1 503 as a mask.
- the width P S38 of the pattern 1511 is the same as the width P S32, and the width P S39 of the pattern 15 12 is the same as the width P S33.
- the interval D2 between the patterns 1511 and 1512 is the same as the interval D1.
- an etching correction process is performed before the conversion of the exposure data format to prevent a phenomenon that the pattern dimension after the etching differs from the pattern dimension of the design data.
- the pattern width is increased in advance in a region where etching proceeds more.
- the exposure time increases as the number of patterns increases.
- the etching correction process is not performed on the dummy pattern, the time for generating the electron beam exposure data and the time for the exposure can be shortened.
- step S503 in FIG. 5 hierarchical processing or the like is performed for each of the repeatedly arranged structures (for example, structure A and structure B in FIG. 3B). Depending on the location In this case, the results of the etching correction are different, and the number of repeatedly arranged structures is reduced. Therefore, the time required for the exposure data format conversion processing increases.
- the exposure data format conversion processing time can be reduced by the structure creation processing in step S605 of FIG.
- the size of the structure area 701 (for example, the X-axis value and the Y-axis value) is described in the control file input to the etching correction process, and after the jetting correction, the size of the structure below the highest-order structure is reduced
- the structure area is divided into a grid pattern with the size of the structure area 701. Data is output with the divided area 7001 as the first type of structure.
- the exposure data format conversion process is performed for each structure 701.
- the name of the structure divided by the size of the area 701 is described.
- the first three characters (for example, "ABC") of the name of the structure output by the etching correction process are described in the input control file, and the exposure data format conversion process is performed for each structure 701 having the first three characters.
- the processing time increases due to the increase in the number of accesses to the magnetic disk (for example, the external storage device 1808 in FIG. 18). Therefore, when the arrangement coordinates and the number of vertices are converted all at once by the number of patterns of the structure 701 that can be loaded on the memory (for example, RAM I 804 in FIG. 18), the number of accesses becomes And the processing time can be reduced.
- the size of the structure area 701 can be different for each layer. For example, in the case of a wiring layer, it can be roughly classified into a layer in which most of the pattern extends in the vertical direction and a layer in which the pattern extends in the horizontal direction.
- the structure 70 1 becomes longer in the layer that extends vertically, and the structure 70 1 in the layer that extends horizontally. Becomes oblong. If the pattern is divided, the number of patterns increases and the processing time increases.
- FIG. 8 is a flowchart showing details of the exposure data format conversion processing in step S503 of FIG.
- control file contains Describe the layer numbers defined for the normal pattern and the dummy pattern, respectively.
- step S802 a collective exposure pattern extraction process is performed. That is, the variable rectangular exposure pattern shown in FIG. 2A and the collective exposure pattern shown in FIG. 2B are separated and extracted from the patterns arranged in the structure described in the control file. That is, a variable rectangular exposure pattern is selected from the variable rectangular exposure pattern and the batch exposure pattern.
- step S803 contour division processing is performed only on the variable rectangular exposure pattern. The details will be described later with reference to FIG.
- step S804 the intermediate data 5 12 in FIG. 5 is converted into exposure data 5 13 according to the format and output.
- FIG. 9 is a flowchart showing details of the contour division processing in step S803 of FIG.
- step S901 it is checked whether or not it is a dummy pattern by referring to the layer number of the control file.
- the control file describes the normal pattern and the layer number defined in the dummy pattern. If it is a normal pattern, the process proceeds to step S 902. If it is a dummy pattern, the process proceeds to step S 903 without performing pattern division (S 902).
- step S902 a pattern dividing process is performed. The details of this processing will be described later with reference to FIG. Thereafter, the flow advances to step S903.
- step S903 it is checked whether or not processing of all patterns has been completed. If the processing has been completed, the processing is terminated. If not completed, the processing returns to step S901, and the processing of the next pattern is performed.
- FIG. 10 is a diagram for explaining the pattern division processing in step S902 of FIG.
- one pattern 100000 is divided into five patterns 1001, 1002, 1003, 1004, and 1005. Specifically, it is divided into a central part 1001 and its outline part 1002, 1003, 1004 and 1005. To do.
- the central portion 1001 decreases the exposure amount
- the contour portion 1002 to 1005 increases the exposure amount. Avoid distortion of pattern shape due to proximity effect. That is, in the proximity effect correction processing, the electron beam exposure amounts of the central portion 1001 and the contour portions 1002 to 1005 are made different.
- the contour division processing can be said to be a part of the proximity effect correction processing.
- contour division pattern division processing is not performed on dummy patterns. Since the contour division process divides the pattern and sets different exposure amounts, the number of patterns increases and the exposure time increases. In the present embodiment, since the contour division processing (proximity effect correction) is not performed on the dummy pattern, the electron beam exposure data generation time and the exposure time can be shortened.
- FIG. 17 is a flowchart showing another example of the electron beam exposure data processing of FIG.
- the design data 5 11 included normal data and dummy patterns.
- the design data (normal data) 17 11, 17 12 and the dummy data 17 13 are stored in different files.
- the design data 1711 is a normal pattern of the first functional block (for example, ROM), and the design data 1712 is
- step S1701 a file synthesizing process is performed.
- the file synthesizing process synthesizes the design data 1711, 1712 and dummy data 1713 files and records the intermediate data 1714 in one file. Thereafter, the same processing as in FIG. 5 is performed for the intermediate data 17 14.
- For the layer number of the output data a different layer number is described for the normal pattern and the dummy pattern.
- the output layer number is defined for the normal pattern and dummy pattern by referring to the control file by the file synthesis processing, and the intermediate data 1
- Output 7 1 4 When synthesizing files of two or more types of design data 1711 and 1712, or to flatten the wafer surface during the wafer process, dummy patterns that do not affect the function of the semiconductor device are used. Can be synthesized.
- FIG. 18 is a block diagram illustrating an example of a hardware configuration of a computer that performs the processes of FIGS. 5 and 17.
- This computer can also create CAD design data.
- the bus 1801 has a central processing unit (CPU) 1802, a ROM 1803, a RAM 1804, a network interface 1805, and an input.
- a device 1 806, an output device 1807 and an external storage device 1808 are connected.
- the CPU 1802 performs data processing and calculation, and controls the above-described configuration unit connected via the bus 1801.
- a boot program is stored in the ROM 1803 in advance, and when the CPU 1802 executes the boot program, the computer is started.
- a computer program is stored in the external storage device 1808, and the computer program is copied to the RAM 1804 and executed by the CPU 1802. This computer executes the processing of FIG. 5 and FIG. 17 by executing a computer program.
- the external storage device 1808 is, for example, a hard disk storage device or the like, and does not lose its stored contents even when the power is turned off.
- the external storage device 1808 can record computer programs, design data, intermediate data, exposure data, control files, and the like on a recording medium, and can read computer programs and the like from the recording medium.
- a network interface 1805 can input and output a computer program, exposure data, and the like to a network.
- the input device 1806 is, for example, a keyboard and a pointing device (mouse), and can perform various designations or inputs.
- the output device 1807 is a display, a printer, or the like.
- This embodiment can be realized by a computer executing a program. Further, means for supplying the program to the computer, for example, a computer-readable recording medium such as a CD-ROM in which the program is recorded, or a transmission medium such as the Internet for transmitting the program is also applied as an embodiment of the present invention. can do. In addition, the compilation that recorded the above program A computer program product such as a data readable recording medium can also be applied as an embodiment of the present invention. The above-described program, recording medium, transmission medium, and computer program product are included in the scope of the present invention.
- a flexible disk for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, and the like can be used.
- a flexible disk for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, and the like can be used.
- the electron beam exposure data of the first type pattern (dummy pattern) is not corrected, and the electron beam exposure data of the second type pattern (normal pattern) is not corrected. Perform capture. Since the dummy pattern does not affect the function of the semiconductor device, unnecessary processing can be eliminated to shorten the time for generating electron beam exposure data and the time for exposure.
- step S502 of FIG. 5 By performing the etching correction process in step S502 of FIG. 5, it becomes possible to keep the pattern dimensions after etching within the range of the standard value. As a result, the yield of semiconductor devices is improved, and costs can be reduced.
- the structure created in the size of the area 701 designated for each layer is obtained.
- the time for the etching correction processing can be reduced, and the exposure time can be reduced along with the number of patterns.
- the amount of accumulated energy due to backscattering from the lower layer is calculated to determine the amount of exposure of the pattern, so that the pattern dimension after development becomes the same as the pattern dimension of the design data. Therefore, the yield of semiconductor devices can be improved and costs can be reduced.
- the first type of pattern is, for example, a dummy pattern that does not affect the function of the semiconductor device, and does not necessarily require correction.
- the second type of pattern is, for example, a normal pattern that affects the function of the semiconductor device, and is a pattern that requires correction.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Electron Beam Exposure (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006512421A JP4431574B2 (ja) | 2004-03-30 | 2004-03-30 | 電子ビーム露光データ補正方法 |
PCT/JP2004/004513 WO2005104193A1 (ja) | 2004-03-30 | 2004-03-30 | 電子ビーム露光データ補正方法 |
EP04724406A EP1732107A4 (en) | 2004-03-30 | 2004-03-30 | METHOD FOR CORRECTING EXPOSURE DATA TO AN ELECTRON BEAM |
US11/506,171 US7569842B2 (en) | 2004-03-30 | 2006-08-18 | Method for correcting electron beam exposure data |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2004/004513 WO2005104193A1 (ja) | 2004-03-30 | 2004-03-30 | 電子ビーム露光データ補正方法 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/506,171 Continuation US7569842B2 (en) | 2004-03-30 | 2006-08-18 | Method for correcting electron beam exposure data |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005104193A1 true WO2005104193A1 (ja) | 2005-11-03 |
Family
ID=35197256
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2004/004513 WO2005104193A1 (ja) | 2004-03-30 | 2004-03-30 | 電子ビーム露光データ補正方法 |
Country Status (4)
Country | Link |
---|---|
US (1) | US7569842B2 (ja) |
EP (1) | EP1732107A4 (ja) |
JP (1) | JP4431574B2 (ja) |
WO (1) | WO2005104193A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009105296A (ja) * | 2007-10-25 | 2009-05-14 | Fujitsu Microelectronics Ltd | ダミーチップ露光方法 |
WO2012169662A1 (en) | 2011-06-07 | 2012-12-13 | Otsuka Pharmaceutical Co., Ltd. | Freeze-dried aripiprazole formulation |
JP2018041920A (ja) * | 2016-09-09 | 2018-03-15 | 株式会社ニューフレアテクノロジー | ブランキングアパーチャアレイ装置、荷電粒子ビーム描画装置、および電極テスト方法 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4431574B2 (ja) * | 2004-03-30 | 2010-03-17 | 富士通マイクロエレクトロニクス株式会社 | 電子ビーム露光データ補正方法 |
JP5205983B2 (ja) * | 2008-01-18 | 2013-06-05 | 富士通セミコンダクター株式会社 | 半導体装置のデータ作成方法、および電子線露光システム |
US7496885B1 (en) | 2008-04-02 | 2009-02-24 | International Business Machines Corporation | Method of compensating for defective pattern generation data in a variable shaped electron beam system |
DE112011103109B4 (de) * | 2010-09-17 | 2023-03-09 | Nippon Control System Corp. | Verfahren zum Berechnen einer optimalen Strahlungsmenge eines Elektronenstrahls, Zeichenvorrichtung und Programm |
JP6523767B2 (ja) * | 2015-04-21 | 2019-06-05 | 株式会社ニューフレアテクノロジー | 荷電粒子ビーム描画装置及び荷電粒子ビーム描画方法 |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0766098A (ja) * | 1993-08-23 | 1995-03-10 | Hitachi Ltd | 描画データ作成方法、及び描画データ作成装置 |
JPH0794378A (ja) * | 1993-09-20 | 1995-04-07 | Fujitsu Ltd | 電子ビーム露光方法 |
JPH09298145A (ja) | 1996-05-07 | 1997-11-18 | Mitsubishi Electric Corp | 電子ビーム描画データ作成装置 |
JPH1090878A (ja) | 1996-09-17 | 1998-04-10 | Nikon Corp | 近接効果補正方法及び同方法に用いるパターン転写用マスク |
JPH10199785A (ja) * | 1997-01-06 | 1998-07-31 | Hitachi Ltd | 電子線描画装置 |
JPH10275762A (ja) * | 1997-03-31 | 1998-10-13 | Nec Corp | 電子線の描画方法 |
JPH10301255A (ja) * | 1997-04-23 | 1998-11-13 | Hitachi Ltd | 電子線マスク描画方法 |
JPH11154635A (ja) * | 1997-11-20 | 1999-06-08 | Nec Corp | 電子線直描方法及び装置 |
JPH11354423A (ja) | 1998-06-05 | 1999-12-24 | Nikon Corp | 近接効果補正方法 |
JP2000269126A (ja) * | 1999-03-19 | 2000-09-29 | Nec Corp | 電子線露光方法及び装置 |
JP2001125252A (ja) * | 1999-10-25 | 2001-05-11 | Fujitsu Ltd | 半導体集積回路の露光方法及び露光装置 |
JP2001267223A (ja) | 2000-03-14 | 2001-09-28 | Hitachi Ltd | 半導体装置の製造方法 |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5834918A (ja) * | 1981-08-26 | 1983-03-01 | Fujitsu Ltd | 電子ビ−ム露光方法 |
JP3179520B2 (ja) * | 1991-07-11 | 2001-06-25 | 株式会社日立製作所 | 半導体装置の製造方法 |
US5849437A (en) * | 1994-03-25 | 1998-12-15 | Fujitsu Limited | Electron beam exposure mask and method of manufacturing the same and electron beam exposure method |
JP2605674B2 (ja) * | 1995-02-20 | 1997-04-30 | 日本電気株式会社 | 微細パターン形成方法 |
KR0165524B1 (ko) * | 1996-07-16 | 1999-03-20 | 김광호 | 포토리소그래피 공정의 노광방법 |
JPH10282635A (ja) * | 1997-04-09 | 1998-10-23 | Sony Corp | パターンデータ補正方法、電子線描画方法、フォトマスク及びその作製方法、露光方法、半導体装置及びその製造方法、並びにパターンデータ補正装置 |
US6316163B1 (en) * | 1997-10-01 | 2001-11-13 | Kabushiki Kaisha Toshiba | Pattern forming method |
US6383693B1 (en) * | 2000-08-24 | 2002-05-07 | Taiwan Semiconductor Manufacturing Company, Ltd. | Method of forming a photomask utilizing electron beam dosage compensation method employing dummy pattern |
KR100393227B1 (ko) * | 2001-07-21 | 2003-07-31 | 삼성전자주식회사 | 전자빔 리소그래피시 선폭변화를 보정하여 노광하는 방법및 이를 기록한 기록매체 |
JP4098502B2 (ja) * | 2001-07-30 | 2008-06-11 | 株式会社東芝 | マスクの製造方法とlsiの製造方法 |
KR100459697B1 (ko) * | 2001-12-27 | 2004-12-04 | 삼성전자주식회사 | 가변적인 후방 산란 계수를 이용하는 전자빔 노광 방법 및이를 기록한 컴퓨터로 읽을 수 있는 기록 매체 |
JP2004177783A (ja) * | 2002-11-28 | 2004-06-24 | Fuji Photo Film Co Ltd | 電子ビーム描画方法 |
US7138629B2 (en) * | 2003-04-22 | 2006-11-21 | Ebara Corporation | Testing apparatus using charged particles and device manufacturing method using the testing apparatus |
JP4463589B2 (ja) * | 2003-08-21 | 2010-05-19 | 富士通マイクロエレクトロニクス株式会社 | 荷電粒子ビーム露光における下層構造に基づく後方散乱強度の生成方法及びその方法を利用した半導体装置の製造方法 |
JP4431574B2 (ja) * | 2004-03-30 | 2010-03-17 | 富士通マイクロエレクトロニクス株式会社 | 電子ビーム露光データ補正方法 |
JP4866683B2 (ja) * | 2006-08-25 | 2012-02-01 | 富士通セミコンダクター株式会社 | 半導体デバイスの製造方法、データ作成装置、データ作成方法、およびプログラム |
-
2004
- 2004-03-30 JP JP2006512421A patent/JP4431574B2/ja not_active Expired - Fee Related
- 2004-03-30 WO PCT/JP2004/004513 patent/WO2005104193A1/ja not_active Application Discontinuation
- 2004-03-30 EP EP04724406A patent/EP1732107A4/en not_active Withdrawn
-
2006
- 2006-08-18 US US11/506,171 patent/US7569842B2/en not_active Expired - Fee Related
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0766098A (ja) * | 1993-08-23 | 1995-03-10 | Hitachi Ltd | 描画データ作成方法、及び描画データ作成装置 |
JPH0794378A (ja) * | 1993-09-20 | 1995-04-07 | Fujitsu Ltd | 電子ビーム露光方法 |
JPH09298145A (ja) | 1996-05-07 | 1997-11-18 | Mitsubishi Electric Corp | 電子ビーム描画データ作成装置 |
JPH1090878A (ja) | 1996-09-17 | 1998-04-10 | Nikon Corp | 近接効果補正方法及び同方法に用いるパターン転写用マスク |
JPH10199785A (ja) * | 1997-01-06 | 1998-07-31 | Hitachi Ltd | 電子線描画装置 |
JPH10275762A (ja) * | 1997-03-31 | 1998-10-13 | Nec Corp | 電子線の描画方法 |
JPH10301255A (ja) * | 1997-04-23 | 1998-11-13 | Hitachi Ltd | 電子線マスク描画方法 |
JPH11154635A (ja) * | 1997-11-20 | 1999-06-08 | Nec Corp | 電子線直描方法及び装置 |
JPH11354423A (ja) | 1998-06-05 | 1999-12-24 | Nikon Corp | 近接効果補正方法 |
JP2000269126A (ja) * | 1999-03-19 | 2000-09-29 | Nec Corp | 電子線露光方法及び装置 |
JP2001125252A (ja) * | 1999-10-25 | 2001-05-11 | Fujitsu Ltd | 半導体集積回路の露光方法及び露光装置 |
JP2001267223A (ja) | 2000-03-14 | 2001-09-28 | Hitachi Ltd | 半導体装置の製造方法 |
Non-Patent Citations (1)
Title |
---|
See also references of EP1732107A4 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009105296A (ja) * | 2007-10-25 | 2009-05-14 | Fujitsu Microelectronics Ltd | ダミーチップ露光方法 |
WO2012169662A1 (en) | 2011-06-07 | 2012-12-13 | Otsuka Pharmaceutical Co., Ltd. | Freeze-dried aripiprazole formulation |
JP2018041920A (ja) * | 2016-09-09 | 2018-03-15 | 株式会社ニューフレアテクノロジー | ブランキングアパーチャアレイ装置、荷電粒子ビーム描画装置、および電極テスト方法 |
Also Published As
Publication number | Publication date |
---|---|
EP1732107A1 (en) | 2006-12-13 |
US7569842B2 (en) | 2009-08-04 |
JPWO2005104193A1 (ja) | 2008-03-13 |
JP4431574B2 (ja) | 2010-03-17 |
US20060284120A1 (en) | 2006-12-21 |
EP1732107A4 (en) | 2009-05-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8945803B2 (en) | Smart subfield method for E-beam lithography | |
JP5001563B2 (ja) | 荷電粒子線描画データの作成方法 | |
JP4751353B2 (ja) | データ検証方法及び荷電粒子ビーム描画装置 | |
JP5139658B2 (ja) | 描画データ処理制御装置 | |
JP2007242824A (ja) | 荷電粒子ビーム描画方法、描画データ作成方法及びプログラム | |
US7569842B2 (en) | Method for correcting electron beam exposure data | |
Abboud et al. | Mask data processing in the era of multibeam writers | |
TWI444843B (zh) | A drawing means for depicting a misrepresentation of a drawing device, and a drawing device | |
JP5063320B2 (ja) | 描画装置及び描画データの変換方法 | |
US9927694B2 (en) | Pattern data generation method, pattern data generation device, and mask | |
JP2011100818A (ja) | 荷電粒子ビーム描画装置及び荷電粒子ビーム描画方法 | |
JP4828460B2 (ja) | 描画データ作成方法及び描画データファイルを格納した記憶媒体 | |
JP2011171510A (ja) | 荷電粒子ビーム描画装置 | |
KR100913327B1 (ko) | 포토 마스크 기록 장치용 마스크 패턴 데이터의 비정상패턴을 검출하는 방법 및 비정상 마스크 패턴 데이터의검출 장치 | |
US10282487B2 (en) | Mask data generation method | |
JP5357530B2 (ja) | 描画用データの処理方法、描画方法、及び描画装置 | |
JP2008235553A (ja) | パターン作成方法、パターン検証方法およびプログラム | |
JP5443224B2 (ja) | 荷電粒子ビーム描画用データの生成方法および荷電粒子ビーム描画用データ生成装置 | |
JP2007281184A (ja) | 電子ビーム描画データ生成方法および電子ビーム描画データ生成装置 | |
JP2000269126A (ja) | 電子線露光方法及び装置 | |
JP4529398B2 (ja) | ダミーパターン情報生成装置、パターン情報生成装置、マスク作成方法、ダミーパターン情報生成方法、プログラム及び上記プログラムを記録したコンピュータ読み取り可能な記録媒体 | |
JP2009295833A (ja) | 描画装置及び描画用データの処理方法 | |
JP2001324794A (ja) | フォトマスクパタンデータ作成方法およびフォトマスク | |
JP2009210984A (ja) | マスクパターンデータ作成方法、フォトマスク作製方法、及び集積回路の製造方法 | |
US9268893B2 (en) | Photolithography mask synthesis for spacer patterning |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2004724406 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 11506171 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2006512421 Country of ref document: JP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: DE |
|
WWP | Wipo information: published in national office |
Ref document number: 2004724406 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 11506171 Country of ref document: US |