CN116974140B - Method for removing Cr layer residue on surface of photomask - Google Patents
Method for removing Cr layer residue on surface of photomask Download PDFInfo
- Publication number
- CN116974140B CN116974140B CN202310953574.XA CN202310953574A CN116974140B CN 116974140 B CN116974140 B CN 116974140B CN 202310953574 A CN202310953574 A CN 202310953574A CN 116974140 B CN116974140 B CN 116974140B
- Authority
- CN
- China
- Prior art keywords
- layer
- photomask
- signal value
- esb
- residual
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 64
- 238000005530 etching Methods 0.000 claims abstract description 34
- 239000002184 metal Substances 0.000 claims abstract description 19
- 238000001514 detection method Methods 0.000 claims abstract description 9
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- 229910016006 MoSi Inorganic materials 0.000 claims 1
- 238000004381 surface treatment Methods 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 description 9
- 238000012790 confirmation Methods 0.000 description 3
- 230000035772 mutation Effects 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
- G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
- G03F1/82—Auxiliary processes, e.g. cleaning or inspecting
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Preparing Plates And Mask In Photomechanical Process (AREA)
- Drying Of Semiconductors (AREA)
Abstract
本申请提供一种光掩模表面Cr层残留的去除方法，涉及光掩模表面处理技术领域，其采用修补机台，包括以下步骤：S1，将光掩模置于修补机台上；S2，对光掩模表面进行ESB信号检测，得到ESB信号值；S3，根据不同金属层在ESB信号值上的差异性，读取出关于Cr层的信号值；S4，根据关于Cr层的信号值，得到Cr层的对应位置；S5，蚀刻Cr层的对应位置，对光掩模表面进行修补，去除光掩模表面的残留Cr层。通过上述步骤，使得光掩模能够在修补机台上进行残留Cr层的去除，省去光掩模的二次曝光流程，减少曝光机台和Process机台的加载时间。
The present application provides a method for removing the residual Cr layer on the surface of a photomask, which relates to the technical field of photomask surface treatment. The method adopts a repairing machine, and includes the following steps: S1, placing the photomask on the repairing machine; S2, performing ESB signal detection on the surface of the photomask to obtain the ESB signal value; S3, reading the signal value of the Cr layer according to the difference in the ESB signal value of different metal layers; S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer; S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask. Through the above steps, the residual Cr layer of the photomask can be removed on the repairing machine, eliminating the secondary exposure process of the photomask, and reducing the loading time of the exposure machine and the process machine.
Description
Technical Field
The application relates to the technical field of photomask surface treatment, in particular to a method for removing Cr layer residues on the surface of a photomask.
Background
In the manufacturing process, the photomask is firstly exposed on a photosensitive quartz substrate by an exposure machine, and then is manufactured by development, etching and the like, so that light-transmitting and light-proof ultrafine patterns are formed on the surface of the photomask, and the light-proof patterns are the remained metal layers.
In the current manufacturing method, a Cr layer is left on the surface of the photomask with high probability. Once the Cr layer remains in critical locations of the pattern, it can cause CD variations at the pattern, affecting wafer-end CD. However, there is no better processing method for the Cr layer residue on the surface of the photomask, and the photomask is usually required to be subjected to a secondary exposure Process, which results in long-time loading of the exposure machine and the Process machine.
Therefore, a new method for removing Cr layer on the surface of photomask is needed, which can remove the residual Cr layer on the surface of photomask on other machines, save the secondary exposure Process of photomask, and reduce the loading time of exposure machine and Process machine.
Disclosure of Invention
In view of this, the embodiments of the present disclosure provide a method for removing Cr layer residue on a photomask, which can remove the Cr layer residue on a repair tool, save a secondary exposure Process of the photomask, and reduce loading time of an exposure tool and a Process tool.
The embodiment of the specification provides the following technical scheme:
the embodiment of the specification provides a method for removing Cr layer residues on the surface of a photomask, which adopts a repairing machine, and comprises the following steps:
S1, placing a photomask on a repairing machine;
s2, ESB signal detection is carried out on the surface of the photomask to obtain an ESB signal value;
S3, reading out signal values related to the Cr layers according to the differences of the ESB signal values of different metal layers;
s4, obtaining the corresponding position of the Cr layer according to the signal value related to the Cr layer;
And S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask.
According to the technical scheme, the repairing machine is adopted to detect the surface of the photomask to obtain the ESB signal value, the signal value related to the Cr layer is obtained according to the difference of each metal layer on the ESB signal value, the corresponding position of the residual Cr layer on the surface of the photomask is obtained according to the acquisition position of the Cr layer signal value, the residual Cr layer is removed in an etching mode, so that the secondary exposure Process can be omitted, the whole Cr layer removal Process is carried out on the repairing machine, the exposure machine and the Process machine are not occupied, the loading time of the exposure machine and the Process machine is reduced, the utilization rate of different machines is improved, and the production efficiency of the photomask is improved.
Preferably, between step S1 and step S2, there is further provided step S100:
And setting the standard signal value of each metal layer so that the standard signal value of each metal layer is greater than 10.
According to the technical scheme, the standard signal value of each metal layer is amplified, and the difference of each metal layer on the ESB signal value is increased, so that the ESB signal value related to the Cr layer can be rapidly obtained according to the larger fluctuation of the ESB signal value by reading the ESB signal value, the position of the Cr layer is rapidly determined, and the confirmation efficiency of the Cr layer is improved.
Preferably, step S5 further includes:
during etching, the ESB signal value is observed to change, and once the ESB signal value is suddenly changed, etching is stopped.
Through the technical scheme, the etching is stopped once the ESB signal value is suddenly changed, so that the main pattern on the photomask can be prevented from being influenced by etching, and the yield of the photomask in the repairing process is ensured.
Preferably, the Cr layer is etched using a plasma gas.
The embodiment of the specification also provides a method for removing Cr layer residues on the surface of a PSM photomask, wherein the surface of the PSM photomask comprises a Mosi layer and a Cr layer, and a repairing machine is adopted, and the method comprises the following steps:
s101, placing a PSM photomask on a repairing machine;
s201, ESB signal detection is carried out on the surface of the PSM photomask, and ESB signal values are obtained;
S301, reading out a signal value related to the Cr layer according to the difference between the Mosi layer and the Cr layer on the ESB signal value;
s401, determining the corresponding position of the Cr layer according to the signal value of the Cr layer;
and S501, etching the corresponding position of the Cr layer, repairing the surface of the PSM photomask, and removing the residual Cr layer on the surface of the PSM photomask.
According to the technical scheme, the repairing machine is adopted to detect the surface of the PSM photomask to obtain the ESB signal value, the signal value related to the Cr layer is obtained according to the difference of the Mosi layer and the Cr layer on the ESB signal value, the corresponding position of the residual Cr layer on the surface of the PSM photomask is obtained according to the acquisition position of the Cr layer signal value, the residual Cr layer is removed in an etching mode, so that a secondary exposure Process can be omitted, the whole Cr layer removal Process is carried out on the repairing machine, the exposure machine and the processing machine are not occupied, the loading time of the exposure machine and the processing machine is shortened, the utilization rate of different machines is improved, and the production efficiency of the PSM photomask is improved.
Preferably, between step S101 and step S201, step S1001 is further provided:
The standard signal values of the Mosi layer and the Cr layer are set so that the standard signal values of the Mosi layer and the Cr layer are both greater than 10.
Preferably, step S501 further includes:
in the etching process, the ESB signal value change of the repairing machine is observed, and once the ESB signal value mutation occurs, the etching is stopped.
Preferably, the Cr layer is etched using a fluorine-containing plasma gas.
Compared with the prior art, the beneficial effects that above-mentioned at least one technical scheme that this description embodiment adopted can reach include at least:
The mask surface is detected through a repairing machine to obtain ESB signal values, signal values related to Cr layers are obtained according to the difference of each metal layer on the ESB signal values, corresponding positions of residual Cr layers on the mask surface are obtained according to the acquisition positions of the Cr layer signal values, the residual Cr layers are removed in an etching mode, so that a secondary exposure Process can be omitted, the whole Cr layer removal Process is carried out on the repairing machine, an exposure machine and a Process machine are not occupied, loading time of the exposure machine and the Process machine is shortened, meanwhile, the utilization rate of different machines is improved, and the production efficiency of the mask is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for removing Cr layer residue on a photomask surface according to the present application;
FIG. 2 is a graph of ESB signal changes obtained by performing ESB signal detection on a repair tool with a photomask according to the present application;
fig. 3 is a flowchart of a method for removing Cr layer residue on a surface of a PSM photomask according to the present application.
Detailed Description
Embodiments of the present application will be described in detail below with reference to the accompanying drawings.
Other advantages and effects of the present application will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present application with reference to specific examples. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
It is noted that various aspects of the embodiments are described below within the scope of the following claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present disclosure, one skilled in the art will appreciate that one aspect described herein may be implemented independently of any other aspect, and that two or more of these aspects may be combined in various ways. For example, apparatus may be implemented and/or methods practiced using any number and aspects set forth herein. In addition, such apparatus may be implemented and/or such methods practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.
It should also be noted that the illustrations provided in the following embodiments merely illustrate the basic concept of the present application by way of illustration, and only the components related to the present application are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.
In addition, in the following description, specific details are provided in order to provide a thorough understanding of the examples. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details.
In the manufacturing process, the photomask is firstly exposed on a photosensitive quartz substrate by an exposure machine, and then is manufactured by development, etching and the like, so that light-transmitting and light-proof ultrafine patterns are formed on the surface of the photomask, and the light-proof patterns are the remained metal layers.
In the current manufacturing method, a Cr layer is left on the surface of the photomask with high probability. Once the Cr layer remains in critical locations of the pattern, it can cause CD variations at the pattern, affecting wafer-end CD. However, there is no better processing method for the Cr layer residue on the surface of the photomask, and the photomask is usually required to be subjected to a secondary exposure Process, which results in long-time loading of the exposure machine and the Process machine.
Based on this, the embodiments of the present disclosure propose a method for removing Cr layer residue on a photomask, which can remove the Cr layer residue on a repair tool, save a secondary exposure Process of the photomask, and reduce loading time of an exposure tool and a Process tool.
The following describes the technical scheme provided by each embodiment of the present application with reference to the accompanying drawings.
As shown in fig. 1, an embodiment of the present disclosure provides a method for removing Cr layer residue on a surface of a photomask, which includes the following steps:
s1, placing the photomask on a repairing machine.
S2, ESB signal detection is carried out on the surface of the photomask, and ESB signal values are obtained.
S3, reading out the signal value of the Cr layer according to the difference of the ESB signal values of different metal layers.
S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer.
And S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask. Wherein the Cr layer is etched by using a plasma gas.
As shown in fig. 2, in the practical application Process, the repair machine is used to read the ESB signal value of the surface of the photomask, the signal value related to the Cr layer is obtained according to the difference of each metal layer on the ESB signal value, the corresponding position of the residual Cr layer on the surface of the photomask is obtained according to the obtaining position of the Cr layer signal value, and the residual Cr layer is removed by etching, so that the secondary exposure Process can be omitted, the whole Cr layer removal Process is performed on the repair machine, the exposure machine and the Process machine are not occupied, the loading time of the exposure machine and the Process machine is reduced, the utilization rate of different machines is improved, and the production efficiency of the photomask is improved.
Further, between step S1 and step S2, step S100 is further provided:
And setting the standard signal value of each metal layer so that the standard signal value of each metal layer is greater than 10.
Specifically, by amplifying the standard signal value of each metal layer, the difference of each metal layer on the ESB signal value can be increased, so that in the process of reading the ESB signal value, the ESB signal value corresponding to the Cr layer can be obtained rapidly according to the larger variation fluctuation of the ESB signal value, the position of the Cr layer can be determined rapidly, the confirmation efficiency of the Cr layer is improved, and the subsequent etching of the Cr layer is facilitated.
Wherein S100 may also be provided before step S1.
Further, step S5 further includes:
during etching, the ESB signal value is observed to change, and once the ESB signal value is suddenly changed, etching is stopped.
The abrupt change of the ESB signal value indicates that the Cr layer at the current position is basically etched, and etching is stopped in time, so that the etching of the main pattern on the photomask can be effectively prevented, and the integrity of the main pattern is maintained.
The embodiment of the specification also provides a method for removing the residual Cr layer on the surface of the PSM photomask, as shown in fig. 3, wherein the surface of the PSM photomask comprises a Mosi layer and a Cr layer, and a repairing machine is adopted, and the method comprises the following steps:
S101, placing the PSM photomask on a repairing machine.
S201, ESB signal detection and ESB signal value are carried out on the surface of the PSM photomask.
S301, reading out a signal value of the Cr layer according to the difference between the ESB signal value of the Mosi layer and the Cr layer.
S401, determining the corresponding position of the Cr layer according to the signal value of the Cr layer.
And S501, etching the corresponding position of the Cr layer, repairing the surface of the PSM photomask, and removing the residual Cr layer on the surface of the PSM photomask. Wherein, the Cr layer is etched by using fluorine-containing plasma gas.
In the practical application process, since the surface of the PSM photomask comprises a Mosi layer and a Cr layer, and ESB signal values obtained by ESB signal detection of the Mosi layer and the Cr layer on the repairing machine are different, when the area where the Cr layer is located is scanned, whether the current area belongs to the Cr layer can be rapidly confirmed according to the ESB signal values, and then the Cr layer is removed in an etching mode. The whole Process is carried out on the repairing machine, so that the exposure machine and the Process machine are not occupied, the loading time of the exposure machine and the Process machine is reduced, the utilization rate of different machines is improved, and the production efficiency of the PSM photomask is improved.
Further, between step S101 and step S201, step S1001 is further provided:
The standard signal values of the Mosi layer and the Cr layer are set so that the standard signal values of the Mosi layer and the Cr layer are both greater than 10.
Specifically, by amplifying standard signal values of the Mosi layer and the Cr layer, a difference between the ESB signal values of the Mosi layer and the Cr layer can be increased, so that in a process of reading the ESB signal values, the ESB signal values corresponding to the Cr layer can be rapidly obtained according to larger variation fluctuation of the ESB signal values, thereby rapidly determining the position of the Cr layer, improving the confirmation efficiency of the Cr layer, and facilitating subsequent etching of the Cr layer.
Further, step S501 further includes:
in the etching process, the ESB signal value change of the repairing machine is observed, and once the ESB signal value mutation occurs, the etching is stopped.
The abrupt change of the ESB signal value indicates that the Cr layer at the current position is basically etched, and etching is stopped in time, so that the etching of the main pattern on the photomask can be effectively prevented, and the integrity of the main pattern is maintained.
In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment focuses on differences from other embodiments.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present application should be included in the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310953574.XA CN116974140B (en) | 2023-07-31 | 2023-07-31 | Method for removing Cr layer residue on surface of photomask |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310953574.XA CN116974140B (en) | 2023-07-31 | 2023-07-31 | Method for removing Cr layer residue on surface of photomask |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116974140A CN116974140A (en) | 2023-10-31 |
| CN116974140B true CN116974140B (en) | 2024-12-24 |
Family
ID=88477777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310953574.XA Active CN116974140B (en) | 2023-07-31 | 2023-07-31 | Method for removing Cr layer residue on surface of photomask |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116974140B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW202225827A (en) * | 2020-12-22 | 2022-07-01 | 德商卡爾蔡司Ｓｍｔ有限公司 | Endpointing by means of contrast gas |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20060085263A (en) * | 2005-01-21 | 2006-07-26 | 삼성전자주식회사 | How to check for mask defects |
| JP4659004B2 (en) * | 2007-08-10 | 2011-03-30 | 株式会社日立ハイテクノロジーズ | Circuit pattern inspection method and circuit pattern inspection system |
| DE102015201268A1 (en) * | 2014-10-27 | 2016-04-28 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method for defect inspection on multilayer mirror layers for EUV or soft X-ray radiation |
-
2023
- 2023-07-31 CN CN202310953574.XA patent/CN116974140B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW202225827A (en) * | 2020-12-22 | 2022-07-01 | 德商卡爾蔡司Ｓｍｔ有限公司 | Endpointing by means of contrast gas |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116974140A (en) | 2023-10-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI353538B (en) | Mask design method, dangerous area verification mo | |
| US8307310B2 (en) | Pattern generating method, method of manufacturing semiconductor device, computer program product, and pattern-shape-determination-parameter generating method | |
| JP4282051B2 (en) | Mask pattern data generation method for semiconductor integrated circuit manufacturing and verification method thereof | |
| US7818709B2 (en) | Circuit-pattern-data correction method and semiconductor-device manufacturing method | |
| US7890908B2 (en) | Method for verifying mask pattern data, method for manufacturing mask, mask pattern verification program, and method for manufacturing semiconductor device | |
| JP5100405B2 (en) | Database creation method and database apparatus | |
| US8443309B2 (en) | Multifeature test pattern for optical proximity correction model verification | |
| CN116974140B (en) | Method for removing Cr layer residue on surface of photomask | |
| JP4621485B2 (en) | Pattern data verification method, pattern data creation method, exposure mask manufacturing method and program | |
| JP2005055563A (en) | Mask correction program, mask correction method and method for manufacturing mask | |
| JP2009175546A (en) | Photomask data verification semiconductor cell and semiconductor chip | |
| CN111258186B (en) | Method for screening light intensity threshold value of SRAF developing on photoresist and predicting risk of SRAF developing by exposure | |
| JP4851924B2 (en) | Hazardous area counting method, pattern correction method and program | |
| JP3650055B2 (en) | Correction method for halftone phase shift mask | |
| JP7110044B2 (en) | Repair pattern generation apparatus, pattern defect repair system, repair pattern generation method, and semiconductor device manufacturing method | |
| JP4568228B2 (en) | Semiconductor integrated circuit automatic design method, semiconductor integrated circuit automatic design system, and semiconductor integrated circuit | |
| JP4330524B2 (en) | Pattern data correction method and semiconductor device manufacturing method | |
| KR101160010B1 (en) | Method for processing optical proximity correction | |
| JP2004157475A (en) | Integrated circuit pattern design method, exposure mask preparation method, exposure mask, and integrated circuit device manufacturing method | |
| CN114167681B (en) | Defect detection method, mask manufacturing method and semiconductor structure forming method | |
| KR20080000976A (en) | Optical proximity effect correction method of semiconductor device pattern | |
| KR20080001439A (en) | Photomask Manufacturing Method Using Modification of Layout Design | |
| KR20110121467A (en) | Pattern Layout Verification Method for Spacer Patterning Process | |
| CN117289537A (en) | Manufacturing method of phase shift mask for reducing chromium residue hard defect | |
| KR101179262B1 (en) | Method of manufacturing a tritone phase shift mask |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Country or region after: China Address after: No. 2 Xinxinguang 1st Street, Xinxinguang Industrial Park, Huangpu District, Guangzhou City, Guangdong Province 510799 Applicant after: Guangzhou Xinrui photomask Technology Co.,Ltd. Address before: 510555 Room 518, room 406, No. 1, Yichuang street, Guangzhou City, Guangdong Province (Zhongxin Guangzhou Knowledge City) Applicant before: Guangzhou Xinrui photomask Technology Co.,Ltd. Country or region before: China |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |