The phase-shifting mask consists of a normal transmission mask that has been coated with a transparent layer patterned to ensure that the optical phases of nearest apertures are opposite. Destructive interference between waves from adjacent apertures cancels some diffraction effects and increases the spatial resolution with which such patterns can be projected. A simple theory predicts a near doubling of resolution for illumination with partial incoherence σ < 0.3, and substantial improvements in resolution for σ < 0.7. Initial results obtained with a phase-shifting mask patterned with typical device structures by electron-beam lithography and exposed using a Mann 4800 10× tool reveals a 40-percent increase in usuable resolution with some structures printed at a resolution of 1000 lines/mm. Phase-shifting mask structures can be used to facilitate proximity printing with larger gaps between mask and wafer. Theory indicates that the increase in resolution is accompanied by a minimal decrease in depth of focus. Thus the phase-shifting mask may be the most desirable device for enhancing optical lithography resolution in the VLSI/VHSIC era.

Improving resolution in photolithography with a phase-shifting mask

The theory of image formation is formulated in terms of the coherence function in the object plane, the diffraction distribution function of the image-forming system and a function describing the structure of the object. There results a four-fold integral involving these functions, and the complex conjugate functions of the latter two. This integral is evaluated in terms of the Fourier transforms of the coherence function, the diffraction distribution function and its complex conjugate. In fact, these transforms are respectively the distribution of intensity in an 'effective source', and the complex transmission of the optical system-they are the data initially known and are generally of simple form. A generalized 'transmission factor' is found which reduces to the known results in the simple cases of perfect coherence and complete incoherence. The procedure may be varied in a manner more suited to non-periodic objects. The theory is applied to study inter alia the influence of the method of illumination on the images of simple periodic structures and of an isolated line.

On the diffraction theory of optical images

A radiation sensitive resin composition comprising (A) a fluorine-containing copolymer of hexafluoropropylene, at least one compound selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides, and an unsaturated compound (B) an acid generating compound which generates an acid upon exposure to radiation; (C) a cross-linkable compound; and (D) an organic solvent. The composition suitable is useful for a negative resist for forming a mask for the production of a circuit such as a semiconductor integrated circuit or a thin film transistor circuit for liquid crystal displays as well as a material for forming a permanent film such as an interlaminar insulating film or a color filter protective film.

Radiation-sensitive resin composition

A lithographic apparatus configured to project a patterned beam of radiation onto a target portion of a substrate is disclosed. The apparatus includes a first radiation dose detector and a second radiation dose detector, each detector comprising a secondary electron emission surface configured to receive a radiation flux and to emit secondary electrons due to the receipt of the radiation flux, the first radiation dose detector located upstream with respect to the second radiation dose detector viewed with respect to a direction of radiation transmission, and a meter, connected to each detector, to detect a current or voltage resulting from the secondary electron emission from the respective electron emission surface.

Lithographic apparatus, and device manufacturing method

The presently claimed invention generally relates to deriving and/or utilizing content signatures (e.g., so-called “fingerprints”). One claim recites a method of generating a fingerprint associated with a content item including: pseudo-randomly selecting a segment of the content item; and utilizing a processor or electronic processing circuitry, fingerprinting the selected segment of content item as at least an identifier of the content item. Of course, other claims and combination are provided as well.

Methods, Apparatus and Programs for Generating and Utilizing Content Signatures

The double line and space (L&S) formation method with L&S masks and dipole illumination was found to have high capability to fabricate about 0.3-k1 contact hole (C/H) pattern. The procedure was as follows. The first L&S pattern was formed and was hardened to avoid the dissolution and mixing during the second resist coating. The second L&S pattern perpendicular to the first one was formed on the first resist pattern. The common space area of the two patterns became 1:1 C/H pattern. Simulation results showed that the double L&S formation method has much wider lithography latitude than other methods, such as single exposure of a C/H mask with quadrupole illumination, single exposure of a vortex mask with conventional illumination, and double exposure of L&S masks with dipole illumination to a single layer resist. 75-nm (0.30-k1) 1:1 C/H pattern was fabricated. 80-nm (0.32-k1) 1:1 C/H pattern had 280 nm and 600 nm depth of focus (DOF) in each resist layer. Moreover, a new method, in which a C/H mask replaces the L&S masks, is proposed to achieve cost reduction and the same high performance as the L&S masks.

Contact hole formation by multiple exposure technique in ultralow-k1 lithography

Although Self-Aligned Double and Quadruple Patterning (SADP, SAQP) have become the most promising processes for sub-20 nm and sub-14 nm node advanced technologies, not all wafer images are realized by them. In advanced technologies, feasible wafer images should be generated effectively by utilizing SADP and SAQP where a wafer image is uniquely determined by a selected mandrel pattern. However, predicting the wafer image of a mandrel pattern is not easy. In this paper, we propose a routing method of generating a feasible wafer image satisfying the connection requirements. Routing algorithms comprising simple connecting and cutting rules are performed on a new grid structure where two (SADP) or three colors (SAQP) are assigned alternately to grid-nodes. Then a mandrel pattern is selected without complex coloring or decomposition methods. Also, hotspot reduction by dummy pattern flipping is proposed. In experiments, feasible wafer images meeting the connection requirements are generated and the effectiveness of the proposed framework is confirmed.

Self-Aligned Double and Quadruple Patterning-aware grid routing with hotspots control

Self-Aligned Double Patterning (SADP) has become one of the most promising processes for 20nm node technology and
beyond. Despite its robustness against overlay, it is a challenging process for designers since predicting the wafer image
instantly is almost impossible. Self-Aligned Quadruple Patterning (SAQP) is also critical technology for sub-10nm
process but more complex than SADP, so it is too difficult to design a layout intuitively. Needless to say designing
layout by applying N times sidewalls intuitively is impossible for almost everyone. In this paper, we clarify a new
intuitive principle for SADP layout. The principle uses "Base patterns" painted in different two colors interchangeably.
The proposed method enables us to design SADP layout simply by connecting and cutting fundamental pattern
arbitrarily with a few restrictions. Another benefit is that either of two colors in the pattern can be used as mandrel. We
can apply the principle to not only SAQP but also N times sidewall processes. Considering these advantages, layout
formed by sidewall process becomes designer-friendly.

Self-aligned double and quadruple patterning layout principle

A mask pattern data producing method is disclosed, which comprises preparing design pattern data in which contact holes are arranged on part of the grid points in matrix, preparing first mask pattern data in which first opening patterns are arranged on all of the grid points, and designing second mask pattern data in which second opening patterns and third opening patterns are arranged, the second opening patterns being arranged on the grid points at which the contact holes are arranged in the design pattern data to include the first opening patterns, the third opening patterns being arranged on a pair of grid points, which is a pair of diagonal grid points only on which the contact holes are arranged in a unit grid formed by four grid points, to include the first opening patterns arranged on the pair of grid points, in place of the second opening patterns.

Mask pattern data producing method, patterning method, reticle correcting method, reticle manufacturing method, and semiconductor apparatus manufacturing method

Directed self-assembly lithography (DSAL), which combines self-assembling materials and a lithographically
defined prepattern, is a potential candidate to extend optical lithography beyond 22 nm. To take full
advantage of DSAL requires diminishing not only systematic error modes but also random error modes by
carefully designing a lithographically defined prepattern and precisely adjusting process conditions. To
accomplish this with satisfactory accuracy, we have proposed a novel method to evaluate DSAL error modes
based on simulations using dissipative particle dynamics (DPD). We have found that we can estimate not only
systematic errors but also random errors qualitatively by simulations.

Shoji Mimotogi

Papers

Contact hole formation by multiple exposure technique in ultralow-k1 lithography

Self-Aligned Double and Quadruple Patterning-aware grid routing with hotspots control

Self-aligned double and quadruple patterning layout principle

Mask pattern data producing method, patterning method, reticle correcting method, reticle manufacturing method, and semiconductor apparatus manufacturing method

Novel error mode analysis method for graphoepitaxial directed self-assembly lithography based on the dissipative particle dynamics method