Masks can be repaired by creating a structure that is different from the original design, but that produces the same aerial image. For example, missing opaque material can be replaced by implanting gallium atoms to reduce transmission and quartz can be etched to an appropriate depth to produce the proper phase. In another aspect, a laser or other means can be used to remove an area of a mask around a defect, and then mask structures, either the intended design structures or alternate structures that produce the same aerial image, can be constructed using charged particle beam deposition and etching. For example, an electron beam can be used to deposit quartz to alter the phase of transmitted light. An electron beam can also be used with a gas to etch quartz to remove a layer including implanted gallium atoms. Gallium staining can also be reduced or eliminated by providing a sacrificial layer that can be removed, along with the implanted gallium atoms, using, for example, a broad ion beam. In another aspect, a charged particle beam can be programmed to etch a defect using three-dimensional information derived from two charged particle beams images of the defect from different angle.

Photolithography mask repair

Solar cells can strongly benefit from optical strategies capable of providing the desired broadband absorption of sunlight and consequent high conversion efficiency. While many diffractive light-trapping structures prove high absorption enhancements, their industrial application rather depends on simplicity concerning the integration to the solar cell concept and the process technology. Here, we show how simple grating lines can perform as well as advanced light-trapping designs. We use a shallow and periodic grating as the basic element of a quasi-random structure, which is highly suitable for industrial mass production. Its checkerboard arrangement breaks the mirror symmetry and is shown, for instance, to enhance the bulk current of a 1 µm slab of crystalline silicon by 125%. We explain its excellent performance by drawing a direct link between a structure’s Fourier series and the implied photocurrent, derived from a large and diverse set of structures. Our design rule thus meets all relevant aspects of light-trapping for solar cells, clearing the way for simple, practical, and yet outstanding diffractive structures, with a potential impact beyond photonic applications.

Light trapping in solar cells: simple design rules to maximize absorption

We investigated the eco-friendly electron beam (EB) lithography using a high-sensitive negative type of water-developable resist material derived from biomass on hardmask layer for tri-layer processes. A water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB lithography was developed for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of trimethylphenylammonium hydroxide. The images of 200 nm line and 800 nm space pattern with exposure dose of 7.0 μC/cm2 and CF4 etching selectivity of 2.2 with hardmask layer were provided by specific process conditions.

Eco-friendly electron beam lithography using water-developable resist material derived from biomass

A mask is formed selectively on a crystalline silicon film containing a catalyst element, and an amorphous silicon film is formed so as to cover the mask. Phosphorus is implanted into the amorphous silicon film and the portion of the crystalline silicon film which is not covered with the mask. The silicon films are then heated by rapid thermal annealing (RTA). By virtue of the existence of the amorphous silicon film, the temperature of the crystalline silicon film is increased uniformly, whereby the portion of the crystalline silicon film covered with the mask is also heated sufficiently and the catalyst element existing in this region moves to the phosphorus-implanted, amorphous portion having high gettering ability. As a result, the concentration of the catalyst element is reduced in the portion of the silicon film covered with the mask. A semiconductor device is manufactured by using this portion.

Method of Manufacturing Semiconductor Device

The invention relates to a method for processing a substrate with a focussed particle beam which incidents on the substrate, the method comprising the steps of: (a) generating at least one reference mark on the substrate using the focused particle beam and at least one processing gas, (b) determining a reference position of the at least one reference mark, (c) processing the substrate using the reference position of the reference mark, and (d) removing the at least one reference mark from the substrate.

Method and apparatus for processing a substrate with a focused particle beam

A photomask repair method including scanning an electron beam across a main surface of the photomask, thereby producing a pattern image of the photomask, identifying the position of a defective portion from the pattern image thus produced, and applying an electron beam to a region to be etched including a defective portion under an atmosphere of a gas capable of performing a chemical etching of a film material forming the photomask pattern, thereby removing a defect. In this method, the electron beam to be applied to the region to be etched is a shaped beam. The electron beam is set such that the side of the electron beam is applied in parallel to a borderline between a non-defective pattern and the defect.

Photomask repair method and apparatus

We developed a nanoimprint lithography (NIL) technology including NIL system, template and resist process for half pitch (hp) 14 nm direct pattering. The latest NIL system NZ2C shows the mix and match overlay (MMO) of 3.4 nm ( $3\sigma$ ) and the template life around 125 lots. Throughput of 80 wafers per hour (wph) was demonstrated using throughput enhancement solutions, such as gas permeable spin-on-carbon (GP-SOC) and multi field dispense (MFD). The hp 14 nm template was fabricated by a self-aligned double patterning (SADP) on a template. Using this template, we fabricated hp 14 nm dense Si lines with a depth of 50 nm on a 300 mm wafer.

Half pitch 14 nm direct pattering with Nanoimprint lithography

According to an aspect of the present invention, there is provided a method for correcting a defect in an EUV mask, the method including: preparing an EUV mask including an absorption layer and an anti-reflection layer forming a pattern; recognizing a defect region in the pattern; defining a first region and a second region on the defect region, the second region extending from a desired pattern edge by a given distance, the first region being defined on the rest; removing the first region of the anti-reflection layer and the absorption layer by irradiating a beam in a first atmosphere; removing the second region of the anti-reflection layer and the absorption layer by irradiating the beam in a second atmosphere; and oxidizing an exposed side surface of the desired pattern edge of the absorption layer.

Defect correction method for euv mask

Currently, repair machines used for advanced photomasks utilize principle method like as FIB, AFM, and EB. There are specific characteristic respectively, thus they have an opportunity to be used in suitable situation. But when it comes to EUV generation, pattern size is so small highly expected as under 80nm that higher image resolution and repair accuracy is needed for its machines. Because FIB machine has intrinsic damage problem induced by Ga ion and AFM machine has critical tip size issue, those machines are basically difficult to be applied for EUV generation. Consequently, we focused on EB repair tool for research work. EB repair tool has undergone practical milestone about MoSi based masks. We have applied same process which is used for MoSi to EUV blank and confirmed its reaction. Then we found some severe problems which show uncontrollable feature due to its enormously strong reaction between etching gas and absorber material. Though we could etch opaque defect with conventional method and get the edge shaped straight by top-down SEM viewing, there were problems like as sidewall undercut or local erosion depending on defect shape. In order to cope with these problems, the tool vender has developed a new process and reported it through an international conference [1]. We have evaluated the new process mentioned above in detail. In this paper, we will bring the results of those evaluations. Several experiments for repair accuracy, process stability, and other items have been done under estimation of practical condition assuming diversified size and shape defects. A series of actual printability tests will be also included. On the basis of these experiments, we consider the possibility of EB-repair application for 20nm pattern.

Prospect of EUV mask repair technology using e-beam tool

There is provided a method for repairing a photo mask in this invention, including, obtaining a first image being a photo mask image including a defect area of the photo mask by a repair apparatus, obtaining a second image being a wafer printing image of the photo mask including the defect area by an inspection apparatus, superimposing the first image and the second image to identify a position of the defect area in the first image, and repairing the defect area by the repair apparatus.

Shingo Kanamitsu

Papers

Photomask repair method and apparatus

Half pitch 14 nm direct pattering with Nanoimprint lithography

Defect correction method for euv mask

Prospect of EUV mask repair technology using e-beam tool

Method for repairing photo mask, system for repairing photo mask and program for repairing photo mask