Method for particle beam-induced processing of a defect of a microlithographic photomask
A method for particle beam-induced processing of a defect of a microlithographic photomask, including the steps of: a1) providing an image of at least a portion of the photomask, b1) determining a geometric shape of a defect in the image as a repair shape, c1) subdividing the repair shape into a number of n pixels in accordance with a first rasterization, d1) subdividing the repair shape into a number of m pixels in accordance with a second rasterization, the second rasterization emerging from a subpixel displacement of the first rasterization, e1) providing an activating particle beam and a process gas at each of the n pixels of the repair shape in accordance with the first rasterization, and f1) providing the activating particle beam and the process gas at each of the m pixels of the repair shape in accordance with the second rasterization.
1 . A method for particle beam-induced processing of a defect of a microlithographic photomask, including the steps of:
a1) providing an image of at least a portion of the photomask,
b1) determining a geometric shape of a defect in the image as a repair shape,
c1) subdividing the repair shape into a number of n pixels in accordance with a first rasterization,
d1) subdividing the repair shape into a number of m pixels in accordance with a second rasterization, the second rasterization emerging from a subpixel displacement of the first rasterization,
e1) providing an activating particle beam and a process gas at each of the n pixels of the repair shape in accordance with the first rasterization, and
f1) providing the activating particle beam and the process gas at each of the m pixels of the repair shape in accordance with the second rasterization.
2 . The method of claim 1 , wherein the subpixel displacement is a displacement, more particularly a lateral displacement, of the first rasterization by a subpixel dimension.
3 . The method of claim 1 , wherein step e1) is repeated before step f1) with a number g of repetition cycles and/or step f1) is repeated with a number h of repetition cycles.
4 . The method of claim 1 , wherein steps e1) and f1) are repeated with a number j of repetition cycles.
5 . The method of claim 1 , wherein the method is applied for particle beam-induced etching of a defect of the microlithographic photomask and/or for particle beam-induced deposition of material on the microlithographic photomask in a region of the defect.
6 . The method of claim 1 , wherein the process gas includes an etching gas and/or a precursor gas.
7 . The method of claim 1 , wherein in step b1) a two-dimensional geometric shape of the defect in the image is determined as a repair shape.
8 . The method of claim 1 , wherein the repair shape is subdivided into the n pixels in such a way that the n pixels are arranged in columns and lines.
9 . The method of claim 1 , wherein the activating particle beam includes an electron beam and/or an ion beam.
10 . The method of claim 1 , wherein the activating particle beam remains in step e1) at each of the n pixels of the repair shape for a predetermined dwell time to initiate a chemical reaction between the process gas and a mask material at a location of the respective pixel.
11 . The method of claim 1 , wherein the activating particle beam remains in step f1) at each of the m pixels of the repair shape for a predetermined dwell time to initiate a chemical reaction between the process gas and a mask material at a location of the respective pixel.
12 . The method of claim 1 , including the steps of:
subdividing the repair shape into a number of li pixels in accordance with at least one further rasterization, with an i-th further rasterization being subdivided into li pixels and the at least one further rasterization emerging from a subpixel displacement of the first, the second or any other one of the at least one further rasterizations, and
providing the activating particle beam and the process gas at each of the li pixels of the repair shape in accordance with the at least one further rasterization.
13 . The method of claim 12 , wherein the activating particle beam is in each case provided successively in a sequence at the n pixels, the m pixels and/or the li pixels of the repair shape, in which sequence a depletion of the process gas is implemented uniformly over the repair shape by a chemical reaction activated by the activating particle beam.
14 . The method of claim 13 , wherein the sequence in which the activating particle beam is successively provided at the n pixels, the m pixels and/or the li pixels of the repair shape has a random distribution.
15 . An apparatus comprising:
a computing device comprising at least one storage device storing at least one computer program including instructions that when executed by the computing device cause the computing device to:
determine a geometric shape of a defect in an image of at least a portion of a microlithographic photomask as a repair shape,
subdivide the repair shape into a number of n pixels in accordance with a first rasterization,
subdivide the repair shape into a number of m pixels in accordance with a second rasterization, the second rasterization emerging from a subpixel displacement of the first rasterization,
control an activating particle beam and a process gas to be provided at each of the n pixels of the repair shape in accordance with the first rasterization, and
control the activating particle beam and the process gas to be provided at each of the m pixels of the repair shape in accordance with the second rasterization.
16 . The apparatus of claim 15 , wherein the subpixel displacement is a displacement, more particularly a lateral displacement, of the first rasterization by a subpixel dimension.
17 . The apparatus of claim 15 , wherein the computing device is configured to:
subdivide the repair shape into a number of li pixels in accordance with at least one further rasterization, with an i-th further rasterization being subdivided into li pixels and the at least one further rasterization emerging from a subpixel displacement of the first, the second or any other one of the at least one further rasterizations, and
control the activating particle beam and the process gas to be provided at each of the li pixels of the repair shape in accordance with the at least one further rasterization.
18 . The apparatus of claim 15 , wherein the computing device is configured to repeat controlling an activating particle beam and a process gas to be provided at each of the n pixels of the repair shape in accordance with the first rasterization, before controlling the activating particle beam and the process gas to be provided at each of the m pixels of the repair shape in accordance with the second rasterization, with a number g of repetition cycles, and/or
the computing device is configured to repeat controlling the activating particle beam and the process gas to be provided at each of the m pixels of the repair shape in accordance with the second rasterization with a number h of repetition cycles.
19 . The apparatus of claim 15 , wherein the computing device is configured to repeat controlling an activating particle beam and a process gas to be provided at each of the n pixels of the repair shape in accordance with the first rasterization, and controlling the activating particle beam and the process gas to be provided at each of the m pixels of the repair shape in accordance with the second rasterization, with a number j of repetition cycles.
20 . The apparatus of claim 17 , wherein the computing device is configured to in each case provide the activating particle beam successively in a sequence at the n pixels, the m pixels and/or the li pixels of the repair shape, in which sequence a depletion of the process gas is implemented uniformly over the repair shape by a chemical reaction activated by the activating particle beam.