Recently, directed self-assembly (DSA) method is focused on as a next generation lithography technique. We performed the DPD simulations to analyze the self-assembling process of block copolymer in DSA using OCTA (in detail, see http://octa.jp) system. Using DPD simulation, we can obtain the phase separated structures at each moment consisted by block copolymer chains. As those structures are consisted by polymer chains, an analysis can be done on those structures. In this paper, we study the dynamics of end particles in the defect annihilation process to understand the dynamics of self-assembling of block copolymer in DSA. From our analysis, the end particles moves in advance than the change of domain structure in the defect annihilation process.
We proposed the DSA simulation technique which is the combined method of two dimensional (2D) SCF and three
dimensional (3D) dissipative particle dynamics (DPD) methods by using the density biased Monte Carlo method. This
combined method has advantages of both an accuracy of SCF and fast and stably-working simulation of 3D DPD
methods regardless of the strong segregation regime. Using our techniques, several results, such as DSA film structure
on the chemical guide, are obtained. We also discuss the availability of our simulation technique using our free software,
OCTA (in detail, see http://octa.jp) system.
Recent studies have shown that the semiconductor industry is seeking the possibility of utilizing both positive tone
photoresist development (PTD) and negative tone photoresist development (NTD) to pursue ultimate pattern resolution.
In particular, a minimal line edge roughness (LER) is one of the key performance indicators. Our current work is aimed
at studying mechanisms of LER generation by simulating dynamics of polymer molecules in NTD using a meso-scale
simulation technique called Dissipative Particle Dynamics (DPD). In DPD method, several neighboring monomers in a
polymer chain are represented by one DPD particle with soft interaction potentials to accelerate calculation of polymer
dynamics. In our previous studies, we performed virtual lithography experiments to study the molecular level polymer
configuration, and investigated the polymer dissolution rate and the resulting LER generation. In the current work, in
order to make this simulation method more practical for resist polymer design, we develop a method to tune the model
parameters by calibrating to the experimental data obtained by development of actual resist polymers.
We studied the line edge structure forming in the negative tone process using meso scale simulations. Our simulation is
based on the dissipative particle dynamics (DPD) method. The simulation model of the lithographic process is developed
in which the dynamics of a polymer chain in continuous model can be observed. In the negative tone process, the cross
linking reaction is the key step to obtain the high resolution patterns. First we develop the model for the cross linking
reaction. From our results in the dissolution test of the film, as the density of cross links increases, the soluble film to the
developing liquid changed to the swelling (or insoluble) one. Once the threshold between soluble and insoluble
conditions with changing the number of cross links, we can perform two kinds of simulations; 1) layered model
simulation, and 2) line pattern simulation. In the layered model, more roughened edge can be found in the case of a thick
interface than in the case of a thin interface. Our simulations can be applicable to study the LER problem and the
dynamics of polymer chain including the chemical reaction will be one of the important origins of LER.
To study line-edge roughness (LER), we develop a simulation method for the formation process of line edges based on the mesoscale simulation of the dissipative particle dynamics (DPD) method. We model the development and rinse processes based on the coarse-grained resist polymer model. It is important that the block copolymer in which the soluble and insoluble blocks are bonded exists at the line edge. Though the soluble part of this block copolymer is stretched out in the development process, it shrinks in the rinse process. The shrunken polymers contribute to the formation of line edges, and LER is very influenced by these polymers. Our simulations help to analyze the formation process of line edges based on resist polymer chain dynamics.
To study the line edge roughness, we developed the simulation method of formation process of line edge based on the
meso-scale simulation of dissipative particle dynamics (DPD) method. We modeled the development and rinse processes
based on the coarse-grained polymer model. It is important that the block copolymer in which the soluble and insoluble
blocks are bonded exists at the line edge. Though the soluble part of this block copolymer is stretched out in the developing process, it becomes shrunk in the rinse process. The shrunk polymers contribute to the formation of line edge, and LER was much influenced by these polymers. These simulations will represent the formation process of line edge based on the polymer chain dynamics.
We studied the formation process of the line edge using meso scale simulations based on the dissipative particle dynamics method. The simulation model of the lithographic process is developed in which the dynamics of a polymer chain can be observed. We perform three kinds of simulations; 1) whole area exposure simulation, 2) line pattern simulation, 3) the simulation including the line edge. From our results, a sharp and a homogeneous interface between soluble and insoluble polymers is best solution to LER problem, although its roughness is the size of the chain dimension. The roughened edge can be found in the case of a wide and a homogeneous interface. These results indicate that our simulations can be applicable to study the LER problem and the dynamics of polymer chain will be one of the important origins of LER.
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