WATERMARK DEFECT REDUCTION BY RESIST OPTIMIZATION
A method is disclosed for lithographic processing. In one aspect, the method comprises obtaining a resist material with predetermined resist properties. The method further comprises using the resist material for providing a resist layer on the device to be lithographic processed. The method further comprises illuminating the resist layer according to a predetermined pattern to be obtained. The obtained resist material comprises a tuned photo-acid generator component and/or a tuned quencher component and/or a tuned acid mobility as to reduce watermark defects on the lithographic processed device. In another aspect, a corresponding resist material, a set of resist materials, use of such materials and a method for setting up a lithographic process are disclosed.
1 . A resist material for use in immersion lithographic processing, the resist material comprising a tuned photo-acid generator component concentration and/or a tuned quencher component concentration so as to reduce watermark defects on the device after immersion lithographic processing using the resist material, whereby the photo-acid generator component concentration and/or the quencher component concentration is substantially larger than concentrations resulting in an optimum process window with the immersion lithographic processing.
2 . The resist material according to claim 1 , wherein the photo-acid generator component concentration is larger than 2 weight percent.
3 . The resist material according to claim 2 , wherein the photo-acid generator component concentration is larger than 3 weight percent.
4 . The resist material according to claim 3 , wherein the photo-acid generator component concentration is smaller than 20 weight percent.
5 . The resist material according to claim 1 , wherein the quencher component concentration is larger than 15 mol percent.
6 . The resist material according to claim 1 , wherein the resist material comprises deprotecting groups having a tuned activation energy.
7 . The resist material according to claim 1 , wherein the resist material comprises polymer based resin having a tuned glass transition temperature.
8 . A method of reducing the sensitivity to watermark defects in immersion lithographic processing, the method comprising using a resist material according to claim 1 .
9 . A method of selecting a resist material with predetermined resist properties for lithographic processing of a device, the method comprising
tuning a resist material by tuning a photo-acid generator component concentration and/or a quencher component concentration so as to reduce the sensitivity to watermark defects on the lithographic processed device thus obtaining a tuned resist material, whereby the photo-acid generator component concentration and/or the quencher component concentration is substantially larger than concentrations resulting in an optimum process window with the immersion lithographic processing.
10 . The method according to claim 9 , wherein tuning the photo-acid generator component concentration comprising selecting a photo-acid generator component concentration larger than 3 weight percent.
11 . The method according to claim 9 , wherein tuning the quencher component concentration comprises selecting a quencher component concentration larger than 15 mol percent.
12 . A method of lithographically processing a device, the method comprising
obtaining a resist material with predetermined resist properties and using the resist material for providing a resist layer on the device to be lithographic processed;
wherein the resist material comprising a tuned photo-acid generator component concentration and/or a tuned quencher component concentration so as to reduce watermark defects on the lithographic processed device whereby the photo-acid generator component concentration and/or the quencher component concentration is substantially larger than concentrations resulting in an optimum process window with the immersion lithographic processing.
13 . The method according to claim 12 , wherein obtaining a resist material with predetermined resist properties comprises obtaining the resist material taking into account lithographic processing parameters relating to a dose or process window to be obtained with the lithographic process.
14 . The method according to claim 12 , wherein obtaining a resist material with predetermined resist properties comprises selecting a resist material from a set of resist materials.
15 . The method according to claim 12 , the method further comprising illuminating the resist layer according to a predetermined pattern to be obtained.
16 . A device manufactured by a process comprising the method of claim 12 .