A method for making a semiconductor memory device comprising a plurality of memory cells for storing one or more data values, the method comprising: exposing a pattern on a wafer for creating structures for a plurality of memory cells for the semiconductor memory device, wherein the pattern is exposed by means of one or more charged particle beams; and varying an exposure dose of the one or more charged particle beams during exposure of the pattern to generate a set of one or more non-common features in one or more structures of at least one of the memory cells, so that the structures of the at least one memory cell differ from the corresponding structures of other memory cells of the semiconductor memory device.

A method for making a semiconductor memory device comprising a plurality of memory cells for storing one or more data values, the method comprising; exposing a pattern on a wafer for creating structures for a plurality of memory cells for the semiconductor memory device, wherein the pattern is exposed by means of one or more charged particle beams; and varying an exposure dose of the one or more charged particle beams during exposure of the pattern to generate a set of one or more non-common features in one or more structures of at least one of the memory cells, so that the structures of the at least one memory cell differ from the corresponding structures of other memory cells of the semiconductor memory device.

The purpose of the present invention is to correct a beam irradiation position shift caused by charging phenomena with high accuracy. A charged particle beam writing method includes virtually dividing a writing region of the substrate so as to have a predetermined mesh size and calculating a pattern density distribution representing an arrangement ratio of the pattern for each mesh region, calculating a dose distribution using the pattern density distribution, calculating an irradiation amount distribution using the pattern density distribution and the dose distribution, calculating a fogging charged particle amount distribution, calculating a charge amount distribution due to direct charge and a charge amount distribution due to fogging charge, calculating a position shift of a writing position based on the charge amount distribution due to direct charge and the charge amount distribution due to fogging charge, correcting an irradiation position using the position shift, and irradiating the corrected irradiation position with the charged particle beam with which a potential of a surface of the substrate becomes higher than a potential of a bottom surface of ae potential regulation member.

An amount of charge of a substrate is promptly and accurately calculated. A charged particle beam writing method includes a step (S100) for virtually dividing a writing region of the writing target substrate in a mesh-like manner and calculating a pattern density representing an arrangement ratio of the pattern for each mesh region, a step (S102) for calculating a dose for each mesh region using the pattern density, a step (S104) for calculating a charge amount based on a film thickness of the resist film formed on the substrate and the calculated dose by using a predetermined function for charge amount calculation, the function using, as variables, the film thickness of the resist film and the dose, a step (S106) for calculating a position shift amount of a writing position from the calculated charge amount, and a step (S108) for correcting an irradiation position of the charged particle beam using the position shift amount.

A multi-beam writing method includes acquiring a plurality of deflection coordinates for deflecting a beam to each of a plurality of pixels which are in each beam pitch region of a plurality of beam pitch regions, a number of pixels to be exposed by a beam in the each beam pitch region during each of tracking control period performed such that the multiple beams collectively follow a movement of a stage, and a deflection movement amount of the multiple beams at a time of tracking reset for resetting a tracking starting position after each of the tracking control period has passed; and generating a deflection sequence defined using the plurality of deflection coordinates, the number of pixels to be exposed during each of the tracking control period, and the deflection movement amount of the multiple beams at the time of tracking reset.

Methods for exposing a desired shape in an area on a surface using a charged particle beam system include determining a local pattern density for the area, based on an original set of exposure information. A pre-proximity effect correction (PEC) maximum dose for the local pattern density is determined, based on a pre-determined target post-PEC maximum dose. The pre-PEC maximum dose is calculated near an edge of the desired shape. Methods also include modifying the original set of exposure information with the pre-PEC maximum dose to create a modified set of exposure information.

A Procedural EBL system implements a user-provided oracle function (e.g., associated with a specific pattern) to generate control instructions for electron beam drive electronics in an on-demand basis. A control system may invoke the oracle function to query the pattern at individual point locations (e.g., individual x,y locations), and/or it may query the pattern over an area corresponding to a current field being addressed by the beam and stage positioner, for example. This Procedural EBL configuration manages control and pattern generation so that the low-level drive electronics and beam column may remain unchanged, allowing it to leverage existing EBL technologies.

An ion implanter includes a beam generator that generates anion beam, a beam scanner that performs reciprocating scan with the ion beam in a first direction, a platen driving device that performs reciprocating motion of a wafer in a second direction perpendicular to the first direction, while holding the wafer so that a wafer processing surface is irradiated with the ion beam subject to the reciprocating scan, and a control device that changes a beam scan speed in the first direction and a wafer motion speed in the second direction in accordance with a beam irradiation position in the first direction and the second direction at which the wafer processing surface is irradiated with the ion beam so that ions having a desired two-dimensional non-uniform dose distribution are implanted into the wafer processing surface.

A method of milling a sample that includes a first layer formed over a second layer, where the first and second layers are different materials, the method comprising: milling the region of the sample by scanning a focused ion beam over the region a plurality of iterations in which, for each iteration, the focused ion beam removes material from the sample generating byproducts from the milled region; detecting, during the milling, the partial pressures of one or more byproducts with a residual gas analyzer positioned to have a direct line of sight to the milled region; generating, in real-time, an output detection signal from the residual gas analyzer indicative of an amount of the one or more byproducts detected; and stopping the milling based on the output signal.

In one embodiment, a charged particle beam writing method includes transferring a substrate to a writing chamber of a charged particle beam writing apparatus by use of a transfer mechanism while maintaining each of the writing chamber and the transfer mechanism at a predetermined temperature, calculating correction amounts for charged particle beams based on correction data for charged particle beam irradiation positions each associated with a previously obtained elapsed time from a predetermined starting point in time of transfer of the substrate and the elapsed time at a point in time of irradiation with each of the charged particle beams, and applying the charged particle beams to positions corrected based on the calculated correction amounts for the charged particle beams to write a pattern on the substrate.