The present teaching provides an illumination device for source mask optimization of the polarization distribution in the illumination pupil of a lithographic optical imaging system.
The illumination device comprises a mirror array located between a radiation source and an illumination pupil, and each mirror element of the mirror array is individually steerable (controllable), and the polarization state of light from each mirror element, or groups of elements, of the mirror array can be selectively controlled, so that the illumination pupil can be filled with a distribution of light that is selectively controlled.
The present teaching provides an illumination device, e.g. for a lithographic optical imaging system, comprising a mirror array located between a radiation source and an illumination pupil, where each mirror element of the mirror array is individually steerable (controllable), and the polarization state of light from each mirror element of the mirror array can be selectively controlled, so that the illumination pupil can be filled with a distribution of light that is selectively controlled.
There are several ways in which the present teaching can be implemented. For example,
a. A retarder coating can be applied to selected mirror elements to control the polarization state of light reflected from each mirror element of the mirror array. In addition, a wave plate can be provided before the mirror array to set the incident polarization, and thereby making the polarization switchable.
b. An additional mirror array can be provided between the mirror array and the illumination pupil, where the additional mirror array receives radiation from the mirror array and directs the radiation to the illumination pupil. Preferably, the additional mirror array is conjugate to the mirror array. Also the system can use any of the following concepts:
i. an intervening relay system located between the mirror arrays.
ii. an array of polarization filters (or retarders) can be located between the mirror arrays.
iii. a wedge of optically active material can be located between the mirror arrays, such that the orientation of linear polarization leaving the wedge depends continuously on the position of the beam in the wedge.
These and other features of the present teaching will be further apparent from the following detailed description and the accompanying drawings.
As described above, th108-6290e present embodiment provides an illumination device for source mask optimization of the polarization distribution in the illumination pupil of a lithographic optical imaging system, e.g. for a lithograph optical imaging system that uses ArF (Argon Fluoride), or KrF (Krypton Fluoride) radiation source.
The illumination device comprises a mirror array (e.g. a Micro-Mirror Array or MMA) located between a radiation source and an illumination pupil, and each mirror element of the mirror array is individually steerable (controllable), and the polarization state of light from each mirror element, or groups of elements, of the mirror array can be selectively controlled, so that the illumination pupil can be filled with a distribution of light that is selectively controlled.
The following description shows various ways in which the present invention can be implemented, and from that description it is believed that various other ways in which the present invention can be implemented will be apparent to those in the art.
Initially, it is believed useful to understand the concept of how an illumination system without polarization control can be implemented with a mirror array (e.g. a Micro-Mirror Array, or MMA) located between the source and the illumination pupil.
In the present embodiment, the mirror array to be used can be, for example, those continuously changing each of orientations of the mirror elements arranged two-dimensionally. Such mirror array can be selected, for example, from the mirror arrays disclosed in U.S. Pat. Nos. 6,900,915, 7,095,546, and 7,884,920. It is also possible to control the orientations of the mirror elements arranged two-dimensionally, in a plurality of discrete steps. The teachings in U.S. Pat. Nos. 6,900,915, 7,095,546, and 7,884,920 are incorporated herein by reference.
In one embodiment of this invention, polarization control is obtained through the retardance of thin films deposited on the individual mirror elements as shown in
In this embodiment, the Fourier transforming optical system between the mirror array and the illumination pupil has a front focal point positioned near the mirror array and a rear focal point positioned near the illumination pupil.
In the illustrative example of
In this embodiment, a lambda/4 plate may be disposed downstream of the Fourier transforming optical system.
In addition, it is contemplated that polarization control in the illumination system can be implemented with a pair of mirror arrays, in the manner schematically shown in
In this embodiment, the Fourier transforming optical system between the second mirror array and the illumination pupil has a front focal point positioned near the second mirror array and a rear focal point positioned near the illumination pupil. In this embodiment, a lambda/4 plate may be disposed downstream of the Fourier transforming optical system.
The present invention can also be implemented by the systems shown in
Although
In this embodiment, the relay system has a first (front) optical group and a second (rear) optical group. The array of polarization filters or retarders disposed in the relay system, typically disposed between the front and rear optical group. A front focal point of the front optical group may be positioned near the first mirror array, a rear focal point of the front optical group may be positioned near the array of polarization filters or retarders, a front focal point of the rear optical group may be positioned near the array of polarization filters or retarders, and a rear focal point of the front optical group may be positioned near the second mirror array.
In another embodiment, shown in
In these embodiments shown in the
An illumination system according to the present teaching can be readily implemented in a lithographic optical imaging system at the time the optical imaging system is constructed. Moreover, because it is integrated into the mirror array, an illumination system according to the present invention can be provided as an upgrade to an existing lithographic optical imaging system, without taking up any more space in the system.
Thus, the foregoing description provides an illumination device for source mask optimization of the polarization distribution in the illumination pupil of a lithographic optical imaging system, e.g. for a lithograph optical imaging system that uses ArF (Argon Fluoride) radiation source. The illumination device comprises a mirror array located between a radiation source and an illumination pupil, and each mirror element of the mirror array is individually steerable (controllable), and the polarization state of light from each mirror element, or groups of mirror elements, of the mirror array can be selectively controlled, so that the illumination pupil can be filled with a distribution of light that is selectively controlled. The foregoing description shows various ways in which the present invention can be implemented, and from that description it is believed that various other ways in which the present invention can be implemented will be apparent to those in the art.
The present application is a continuation from the U.S. patent application Ser. No. 13/662,140, filed on Oct. 26, 2012 and now published as US 2013/0148359, which in turn claims priority from U.S. Provisional Patent Application No. 61/628,314, filed on Oct. 28, 2011, and titled “Illumination Device for Optimizing Polarization in an Illumination Pipil”. The disclosure of each of the above-identified applications is incorporated by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
6913373 | Tanaka et al. | Jul 2005 | B2 |
20070146676 | Tanitsu et al. | Jun 2007 | A1 |
20070188730 | Takeuchi et al. | Aug 2007 | A1 |
20070296936 | Kato et al. | Dec 2007 | A1 |
20080030707 | Tanaka et al. | Feb 2008 | A1 |
20090109417 | Tanitsu | Apr 2009 | A1 |
20090117494 | Owa | May 2009 | A1 |
20090128886 | Hirota | May 2009 | A1 |
20090135392 | Muramatsu | May 2009 | A1 |
20100165318 | Fiolka et al. | Jul 2010 | A1 |
20110228247 | Mulder | Sep 2011 | A1 |
20130077077 | Saenger | Mar 2013 | A1 |
Number | Date | Country |
---|---|---|
0779530 | Jun 1997 | EP |
2010040506 | Apr 2010 | WO |
2010037476 | Aug 2010 | WO |
2011147658 | Dec 2011 | WO |
Number | Date | Country | |
---|---|---|---|
20170328538 A1 | Nov 2017 | US |
Number | Date | Country | |
---|---|---|---|
61628314 | Oct 2011 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 13662140 | Oct 2012 | US |
Child | 15666162 | US |