DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 8, 9, 15, and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Sugita et al. [US 6,930,754].
For claim 1, Sugita teaches a method of operating a microlithographic projection exposure apparatus comprising an illumination system, the method comprising:
repeatedly exposing a mask to exposure radiation provided by the illumination system (coarse exposure and fine exposure, see Figs. 1, 2, 4, and 12); and
in each exposure, imaging mask structures on one of a multiplicity of fields (shot regions, see col. 16 lines 20-24) of a plurality of semiconductor substrates (plurality of wafers, see col. 20 lines 3-11), wherein the method comprises:
during a period in which the repeated exposure of the mask takes place, successively using the illumination system in first and second illumination settings of the illumination system (effective light sources, see Fig. 1, 2, 4, 6, 7, and 12 and col. 16 lines 25-57), the first illumination setting having a first illumination distribution of the exposure radiation in a pupil plane of the illumination system (first aperture stop 1 of the illumination system 12 for the first illumination mode), the second illumination setting having a second illumination distribution of the exposure radiation in the pupil plane of the illumination system (second aperture stop 2 of the illumination system 12 for the second illumination mode), the second illumination distribution setting being different from the first illumination setting so that: i) a pupil surface illuminated in the first illumination setting has no overlap with a pupil surface illuminated in the second illumination setting (dual pole with small σ of 0.1 at 0.45 radius and circular with large σ of 0.6, or rotated dual pole of 90°, see col. 16 lines 25-57 and col. 17 lines 48-67); or ii) a pupil surface illuminated in the first illumination setting has an overlap of a maximum of 90% of a pupil surface illuminated in the second illumination setting; and
fully exposing the mask at least once in each of the two different illumination settings (step and repeat or step and scan exposure of the same mask, see exposure pattern in Figs. 4 and 12 and col. 16 lines 20-51).
For claim 15, Sugita teaches a method of operating a microlithographic projection exposure apparatus comprising an illumination system, the method comprising:
a) fully exposing a mask to exposure radiation provided by the illumination system in a first illumination setting (first aperture stop 1 of the illumination system 12 for the first illumination mode, see Fig. 1, 2, 4, 6, 7, and 12 and col. 16 lines 25-57 and col. 17 lines 48-67);
b) during a), imaging mask structures on one of a multiplicity of fields (shot regions, see col. 16 lines 20-24) of a plurality of semiconductor substrates (plurality of wafers, see col. 20 lines 3-11);
c) after b), fully exposing the mask to exposure radiation provided by the illumination system in a second illumination setting (second aperture stop 2 of the illumination system 12 for the second illumination mode); and
d) during d), imaging mask structures on one of a multiplicity of fields (shot regions, see col. 16 lines 20-24) of the plurality of semiconductor substrates (plurality of wafers, see col. 20 lines 3-11),
wherein: the first illumination setting has a first illumination distribution of the exposure radiation in a pupil plane of the illumination system (first aperture stop 1 of the illumination system 12 for the first illumination mode); the second illumination setting has a second illumination distribution of the exposure radiation in the pupil plane of the illumination system (second aperture stop 2 of the illumination system 12 for the second illumination mode); and the second illumination distribution setting is different from the first illumination setting so that: i) a pupil surface illuminated in the first illumination setting has no overlap with a pupil surface illuminated in the second illumination setting (dual pole with small σ of 0.1 at 0.45 radius and circular with large σ of 0.6, or rotated dual pole of 90°, see col. 16 lines 25-57 and col. 17 lines 48-67); or ii) a pupil surface illuminated in the first illumination setting has an overlap of a maximum of 90% of a pupil surface illuminated in the second illumination setting.
For claims 8 and 20, Sugita teaches in either of the first and second illumination settings, an illumination distribution or an illumination distribution with a deviation of no more than 5% is assigned to a plurality of field points in the mask plane (points within an illumination field of the mask during a scan or shot exposure, see Figs. 1 and 33).
For claim 9, Sugita teaches the plurality of field points form a contiguous region in the mask plane (points within an illumination field of the mask during a scan or shot exposure, see Figs. 1 and 33).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 2, 10-12, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Sugita.
For claims 2 and 16, Sugita fails to explicitly teach switching between the first and second illumination settings, there is a time interval of less than 200 minutes.
Sugita teaches that no development is provided between fine and coarse exposures (see col. 13 lines 5-7) and that the multiple exposures in a single apparatus reduces the need to move the wafer through multiple apparatus, reducing the time for exposure (see col. 8 lines 17-27).
Accordingly, Sugita recognizes the need for rapid exposure by both of the illumination settings is a result effective parameter that increases throughput.
Further, there is no evidence showing the criticality of the claimed time frame.
According to well established patent law precedent (see, for example, M.P.E.P. §2144.05) it would have been obvious to one of ordinary skill in the art at prior to the effective filing date of the claimed invention to determine (for example by routine experimentation) the optimum time interval between exposure by the first and second illumination settings in order to maintain throughput.
For claims 10-12, Sugita teaches in each of the first and second illumination settings, an area of a lithographic process window for imaging a predetermined type of mask structures is smaller than an area of an assigned optimized lithographic process window (coarse exposure latitude is smaller than the fine exposure latitude and dual exposure latitude, see Fig. 5); the area of a lithographic process window for imaging the predetermined type of mask structures does not take into account thermal wavefront aberrations that are due to thermal heating effects in a projection lens of the projection exposure apparatus caused by the exposure radiation (no thermal heating effects taken into account, only mask pattern and illumination mode, see Figs. 3 and 5, permissible exposure amount is extended to be about double in the case of exposure of a negative type resist or to about triple in the case of exposure of a positive type resist, see col. 14 lines 16-37); and the area of the assigned optimized lithographic process window is optimized for imaging the given type of mask structures by varying the illumination setting (dual exposure), wherein, in one of the first and second illumination settings, the area of the lithographic process window is optimized for imaging a predetermined type of mask structures without taking into account the thermal wavefront aberrations (dual exposure, no thermal heating effects taken into account, only mask pattern and illumination mode, see Figs. 3 and 5 and col. 14 lines 16-37) wherein, in at least one of the first and second illumination settings, the area of the lithographic process window for imaging a predetermined type of mask structures without taking into account the thermal wavefront aberrations is smaller than the area of the assigned optimized process window (coarse exposure latitude is smaller than the fine exposure latitude and dual exposure latitude, see Fig. 5).
Accordingly, Sugita recognizes that a smaller process window of a first or second illumination setting relative to an optimized process window is an inherent feature required to be able to improve the exposure latitude.
Sugita fails to explicitly teach that in each of the first and second illumination settings, an area of a lithographic process window for imaging a predetermined type of mask structures is no more than 20% smaller than an area of an assigned optimized lithographic process window and in at least one of the first and second illumination settings, the area of the lithographic process window for imaging a predetermined type of mask structures is at least 5% smaller than the area of the assigned optimized process window.
There is no evidence showing the criticality of the claimed area variation between the optimized process window and the process window of the first and second illumination setting.
According to well established patent law precedent (see, for example, M.P.E.P. §2144.05) it would have been obvious to one of ordinary skill in the art at prior to the effective filing date of the claimed invention to determine (for example by routine experimentation) the optimum process window area variation for each setting from the optimum process window area in order to ensure a desired exposure latitude for all features of the mask pattern.
Claims 3-7, 14, and 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Sugita in view of Zimmermann et al. [US 2015/0153652].
For claims 3-7, 14, and 17-19, Sugita fails to teach each of the pupil surfaces illuminated in the first and second illuminations comprises a plurality of surface portions that are separated from one another, wherein switching from the first illumination setting to the second illumination setting comprises incrementally switching the illumination distribution in the pupil plan from the distribution of the first illumination setting to the distribution of the second illumination setting, wherein switching from the first illumination setting to the second illumination setting comprises incrementally adapting the first illumination distribution to the second illumination distribution wherein: the illumination system comprises a pupil facet optical unit which comprises a plurality of individual optical units arranged in a pupil plane of the illumination system; the illumination system comprises a field facet optical unit arranged in a plane conjugate to a mask plane in which the mask is disposed; the field facet optical unit comprises a plurality of further individual optical units configured to irradiate the individual optical units of the pupil facet optical unit for the respective formation of a radiation channel of the beam path of the illumination radiation; and the incremental adaptation of the first illumination distribution to the second illumination distribution comprises switching between different radiation channels by successively moving one or more of the individual optical units of the field facet optical unit, wherein each of the first and second illumination distributions is assigned to at least one uniform field point in a mask plane in which the mask is disposed, wherein the exposure radiation is in the EUV wavelength range.
Zimmermann teaches each of the pupil surfaces illuminated in the first and second illuminations comprises a plurality of surface portions that are separated from one another (switching illumination channels, see Figs. 5a and 5b), wherein switching from the first illumination setting to the second illumination setting comprises incrementally switching the illumination distribution in the pupil plan from the distribution of the first illumination setting to the distribution of the second illumination setting (varying the illumination channels from one channel to another channel or turning off a channel, where a channel switch is less than 10% of the original, see [0090]), wherein switching from the first illumination setting to the second illumination setting comprises incrementally adapting the first illumination distribution to the second illumination distribution varying the illumination channels from one channel to another channel or turning off a channel, where a channel switch is less than 10% of the original, see [0090]), wherein: the illumination system comprises a pupil facet optical unit which comprises a plurality of individual optical units arranged in a pupil plane of the illumination system (pupil facet mirror 17, see Fig. 1); the illumination system comprises a field facet optical unit arranged in a plane conjugate to a mask plane in which the mask is disposed (field facet mirror 13, see Fig. 1); the field facet optical unit comprises a plurality of further individual optical units configured to irradiate the individual optical units of the pupil facet optical unit for the respective formation of a radiation channel of the beam path of the illumination radiation (illumination channels between the facets, see [0068]); and the incremental adaptation of the first illumination distribution to the second illumination distribution comprises switching between different radiation channels by successively moving one or more of the individual optical units of the field facet optical unit (swiveling the field facets, see [0030]), wherein each of the first and second illumination distributions is assigned to at least one uniform field point in a mask plane in which the mask is disposed (overlapping field points in pupil distribution on object field, see [0070]), wherein the exposure radiation is in the EUV wavelength range (EUV radiation source [0062]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the incremental changes in the pupil shape using a facet system with a EUV source as taught by Zimmermann in the illumination system as taught by Sugita in order to optimize the illumination settings for a variety of the patterns that vary in directions of 90 degrees and provide illumination that are more complex than simple dipole illumination to reduce variation in critical dimension for each of the settings and to provide a small exposure wavelength to increase resolution.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Sugita in view of Kneer et al. [US 2013/0044303].
For claim 13, Sugita fails to teach in a configuration of the mask structures and the illumination distribution of at least one of the first and second illumination settings, thermal heating effects in a projection lens of the projection exposure apparatus, which occur within a period of time in which the mask is exposed with the respective illumination setting, are taken into account.
Kneer teaches in a configuration of the mask structures and the illumination distribution of at least one of the first and second illumination settings, thermal heating effects in a projection lens of the projection exposure apparatus, which occur within a period of time in which the mask is exposed with the respective illumination setting, are taken into account (altering the illumination setting, such that exceeding of the threshold would need to be feared, see [0068] and [0069] and Fig. 3).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the adjustment based on thermal effects cause by multiple thermal effects as taught by Kneer in the illumination settings as taught by Sugita in order to reduce damage of the optics in the projection system.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Schlesener et al. [US 2015/0301455] teaches an exposure apparatus for providing multiple illumination settings in over multiple passes.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Steven H Whitesell whose telephone number is (571)270-3942. The examiner can normally be reached Mon - Fri 9:00 AM - 5:30 PM (MST).
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/Steven H Whitesell/Primary Examiner, Art Unit 1759
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