Multi head scanning lithographic laser writer and a method for operating
A scanning lithographic laser writer, comprises a substrate holder, an irradiation arrangement and a control unit. The irradiation arrangement has a laser source, a multi head modulator arrangement and at least two writing head arrangements. The irradiation arrangement is arranged for providing laser light, via the multi head modulator arrangement to the writing head arrangements to irradiate a substrate plane. The control unit is configured for controlling a relative mechanical displacement between a substrate holder and the writing head arrangements, and for controlling a sweep of laser light exiting therefrom. The multi head modulator arrangement is configured to split and modulate an input beam into at least one modulated beam for each of the writing head arrangements by use of an acoustic-optical crystal. The writing head arrangements are positioned to displace laser light exiting from the writing head arrangements with respect to each other.
1 . A scanning lithographic laser writer, comprising:
a substrate holder having attachment means for holding a substrate with a laser-light sensitive surface in a substrate plane;
an irradiation arrangement, said irradiation arrangement having a laser source, said irradiation arrangement arranged for providing laser light from said laser source to irradiate said substrate plane, said irradiation arrangement further having a multi head modulator arrangement and m writing head arrangements, where m≥2, said irradiation arrangement arranged for providing said laser light from said laser source, via said multi head modulator arrangement to said m writing head arrangements to irradiate said substrate plane; and
a control unit, said control unit being configured for controlling a relative mechanical displacement between said substrate holder and said m writing head arrangements in at least one scan direction parallel to said substrate plane, said control unit being configured for controlling a sweep of laser light exiting from each of said m writing head arrangements in a sweep direction parallel to said substrate plane and transverse to said at least one scan direction,
wherein said multi head modulator arrangement is configured to split an input beam originating from said laser source into n beams, where n≥1, for each of said m writing head arrangements by use of an acousto-optical crystal, and wherein said multi head modulator arrangement is further configured to modulate said n beams simultaneously into n modulated beams, and
wherein said m writing head arrangements are positioned such that the laser light exiting from each of said m writing head arrangements becomes displaced with a predetermined non-zero distance in the sweep direction with respect to each other.
2 . The scanning lithographic laser writer according to claim 1 , wherein said multi head modulator arrangement comprises an acousto-optical modulator having n modulator segments, wherein each segment is configured to split and modulate the input beam originating from said laser source into one modulated beam for each of said m writing head arrangements.
3 . The scanning lithographic laser writer according to claim 2 , wherein each modulator segment of said acousto-optical modulator comprises m transducers.
4 . The scanning lithographic laser writer according to claim 3 , wherein said m transducers are driven by separate, respective head-assigned frequencies, wherein the separate, respective head-assigned frequencies are different from each other.
5 . The scanning lithographic laser writer according to claim 4 , wherein said multi head modulator arrangement comprises m beam-splitter arrangements, one for each modulator segment of said acousto-optical modulator, configured for splitting said input beam into m incident beams, said m incident beams being provided to said acousto-optical crystal in different incident angles relative to the acousto-optical modulator.
6 . The scanning lithographic laser writer according to claim 3 , wherein each transducer of said m transducers is driven by a radio-frequency signal being a sum of m radio-frequency signals, the m radio-frequency signals each having a respective different frequency, where the m radio-frequency signals of separate radio-frequency signals driving separate transducers of the m transducers have different frequency shifts.
7 . The scanning lithographic laser writer according to claim 6 , wherein said multi head modulator arrangement comprises m beam-splitter arrangements, one for each modulator segment of said acousto-optical modulator, configured for splitting said input beam into m incident beams, said m incident beams being provided to said acousto-optical crystal in different incident angles relative to the acousto-optical modulator.
8 . The scanning lithographic laser writer according to claim 3 , wherein said multi head modulator arrangement comprises m beam-splitter arrangements, one for each modulator segment of said acousto-optical modulator, configured for splitting said input beam into m incident beams, said m incident beams being provided to said acousto-optical crystal in different incident angles relative to the acousto-optical modulator.
9 . The scanning lithographic laser writer according to claim 3 , wherein said predetermined non-zero distance of each writing head arrangement of the m writing head arrangements relative to one or two other writing head arrangements of the m writing head arrangements is equal to an efficient sweep length divided by an integer k, where k≤m, and where said efficient sweep length is a sweep length of said m writing head arrangements minus a sweep overlap distance, said sweep overlap distance being equal to or larger than zero.
10 . The scanning lithographic laser writer according to claim 2 , wherein each modulator segment of said acousto-optical modulator comprises one transducer, wherein said one transducer is driven by a radio-frequency signal being a sum of m radio-frequency signals, each radio-frequency signal of the m radio-frequency signals having a respective different head-assigned frequency.
11 . The scanning lithographic laser writer according to claim 10 , wherein said multi head modulator arrangement comprises m beam-splitter arrangements, one for each modulator segment of said acousto-optical modulator, configured for splitting said input beam into m incident beams, said m incident beams being provided to said acousto-optical crystal in different incident angles relative to the acousto-optical modulator.
12 . The scanning lithographic laser writer according to claim 2 , wherein said predetermined non-zero distance of each writing head arrangement of the m writing head arrangements relative to one or two other writing head arrangements of the m writing head arrangements is equal to an efficient sweep length divided by an integer k, where k≤m, and where said efficient sweep length is a sweep length of said m writing head arrangements minus a sweep overlap distance, said sweep overlap distance being equal to or larger than zero.
13 . The scanning lithographic laser writer according to claim 2 , further comprising a beam separator arranged for separating a bundle of parallel modulated beams from said acousto-optical modulator into m separate groups of n modulated beams, one group for each writing head arrangement.
14 . The scanning lithographic laser writer according to claim 1 , wherein said predetermined non-zero distance of each m writing head arrangement of the m writing head arrangements relative to one or two other writing head arrangements of the m writing head arrangements is equal to an efficient sweep length divided by an integer k, where k≤m, and where said efficient sweep length is a sweep length of said m writing head arrangements minus a sweep overlap distance, said sweep overlap distance being equal or larger than zero.
15 . A method for operating a scanning lithographic laser writer, the method comprising:
providing a laser input beam;
splitting said laser input beam into n beams and, by acoustic-optical modulation, modulating said n beams simultaneously into n modulated beams, where n≥1, for each of m writing head arrangements, where m≥2;
optically connecting said n modulated beams to respective writing head arrangements of the m writing head arrangements;
irradiating a substrate plane of said scanning lithographic laser writer by said n modulated beams for said m writing head arrangements;
displacing said substrate plane and said m writing head arrangements relative to each other in at least a scan direction parallel to said substrate plane; and
sweeping said n modulated beams exiting from said m writing head arrangements in a sweep direction parallel to said substrate plane and transverse to said scan direction,
whereby said n modulated beams exiting from each of said m writing head arrangements at all instances are displaced with a predetermined non-zero distance in the sweep direction with respect to each other.
16 . The method according to claim 15 , wherein the splitting and the modulating is performed in n segment steps, wherein each segment step modulates one beam for each of said m writing head arrangements.
17 . The method according to claim 16 , wherein the splitting and the modulating comprises driving an acousto-optical modulator by m transducers.
18 . The method according to claim 17 , wherein said m transducers are driven by separate, respective head-assigned frequencies, wherein the separate, respective head-assigned frequencies are different from each other.
19 . The method according to claim 17 , wherein each transducer of said m transducers is driven by a radio-frequency signal being a sum of m radio-frequency signals, the m radio-frequency signals each having a respective different frequency, where the m radio-frequency signals of separate radio-frequency signals driving separate transducers of the m transducers have different frequency shifts.
20 . The method according to claim 16 , wherein the splitting and the modulating comprises driving an acousto-optical modulator by one transducer, wherein said one transducer is driven by a radio-frequency signal being a sum of m radio-frequency signals, each radio-frequency signal of the m radio-frequency signals having a respective different head-assigned frequency.