Charged Particle Beam Apparatus, Image Forming Method Using a Charged Particle Beam Apparatus, and Image Processing Apparatus

Patent metadata

Field	Value
Publication number	US-2016276128-A1
Application number	US-201615041873-A
Country	US
Kind code	A1
Filing date	Feb 11, 2016
Priority date	Mar 20, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

To provide a charged particle beam apparatus capable of obtaining an image with high contrast and high visibility, the apparatus has: a charged particle optical system; a detection part to detect secondary charged particles generated from the sample; an image formation part to receive a detection signal from the detection part and form an image of the sample; an image processing part to process the image formed with the image formation part; and a display part to display the result of processing with the image processing part, wherein the image formation part has a pulse-count signal processing part to generate cumulative histogram information on a pulse signal component in the detection signal, set a threshold value for pulse signal detection using information on the generated cumulative histogram, and output a detection signal having a value higher than the set threshold value as a pulse signal.

First claim

What is claimed is:

1 . A charged particle beam apparatus comprising:
a charged particle optical system that emits a converged charged particle beam and scans the beam on a surface of a sample; a detection part that detects secondary charged particles which are generated from the sample irradiated with the charged particle beam with the charged particle optical system; an image formation part that receives a detection signal from the detection part and forms an image of the sample; an image processing part that processes the image formed with the image formation part; and a display part that displays the result of processing with the image processing part, wherein the image formation part has a pulse-count signal processing part that generates cumulative histogram information on a pulse signal component in the detection signal from the detection part, sets a threshold value for pulse signal detection using the generated cumulative histogram information, and outputs a detection signal having a value higher than the set threshold value as a pulse signal.

2 . The charged particle beam apparatus according to claim 1 , wherein the image formation part further includes a pulse-count image formation part, and forms an image based on the pulse signal component using pulse signal information outputted from the pulse-count signal processing part.

3 . The charged particle beam apparatus according to claim 1 , wherein the image formation part has:
a pulse count part that counts the number of pulses in corresponding positions of plurality of frames from the pulse signal information for the plurality of frames outputted from the pulse-count signal processing part, when the charged particle optical system repeatedly emitting the converged charged particle beam and scanning the beam in a predetermined region of the surface of the sample a plurality of times; a brightness gradation setting part that sets brightness gradation of the image from information on the number of pulses counted with the pulse count part; and an image formation part that forms an image using the information on the number of pulses by each position of the plurality of frames counted with the pulse count part and the information on the brightness gradation of the image set with the brightness gradation setting part.

4 . The charged particle beam apparatus according to claim 1 , wherein the image formation part further has:
an analog signal detection part that processes a signal of a low frequency component in the detection signal from the detection part and forms an image; and an integrated image combining part that integrates the images formed with the analog signal detection part.

5 . The charged particle beam apparatus according to claim 1 , wherein the image processing part processes the image formed with the image formation part, to measure the size of a pattern formed on the sample, and the display part displays information on the size of the pattern measured with the image processing part.

6 . An image forming method using a charged particle beam apparatus including the steps of:
emitting a converged charged particle beam and scanning the beam on a surface of a sample with a charged particle optical system; detecting, with a detection part, secondary charged particles which are generated from the sample irradiated with the charged particle beam with the charged particle optical system; receiving a detection signal from the detection part and forming an image of the sample with an image formation part; processing the image formed with the image formation part by an image processing part; and displaying the result of processing with the image processing part by a display part, wherein the step of forming an image of the sample including: generating cumulative histogram information of a pulse signal component in a detection signal from the detection part; setting a threshold value for pulse signal detection using the generated cumulative histogram information; extracting a detection signal having a value higher than the set threshold value as a pulse signal; and forming an image based on the pulse signal component using the information on the extracted pulse signal.

7 . The image forming method using the charged particle beam apparatus according to claim 6 , wherein the image formation based on the pulse signal component is performed by:
counting the number of pulses in corresponding positions of a plurality of frames from pulse signal information for the plurality of frames obtained by repeatedly emitting the converged charged particle beam and scanning the beam in a predetermined region of the surface of the sample a plurality of times with the charged particle optical system; setting brightness gradation of the image from information on the counted number of pulses; and forming an image using the information on the number of pulses by each position of the plurality of frames and the information on the set brightness gradation of the image.

8 . The image forming method using the charged particle beam apparatus according to claim 6 , wherein the image formation with the image formation part further includes:
processing a signal of a low frequency component in the detection signal from the detection part and forming an image; and combining images by integrating the formed images.

9 . The image forming method using the charged particle beam apparatus according to claim 6 , wherein the image processing with the image processing part includes:
processing the image formed with the image formation part to measure a size of a pattern formed on the sample; and displaying information on the size of the pattern measured with the image processing part with the display part.

10 . An image processing apparatus for forming an image of a sample and receiving a signal from a detection part that detects secondary charged particles, occurring from the sample by emitting a charged particle beam converged with a charged particle beam apparatus on a surface of the sample and scanning the beam, the image processing apparatus comprising:
a pulse-count signal processing part that generates cumulative histogram information on a pulse signal component in the detection signal from the detection part, sets a threshold value for pulse signal detection using the generated cumulative histogram information, and outputs a detection signal having a value higher than the set threshold value as a pulse signal; and a pulse-count image formation part that forms an image based on the pulse signal component using pulse signal information outputted from the pulse-count signal processing part.

11 . The image processing apparatus according to claim 10 , wherein the pulse-count signal processing part has:
a pulse count part that counts the number of pulses in corresponding positions of plurality of frames from the pulse signal information for the plurality of frames outputted from the pulse-count signal processing part, when the charged particle optical system has repeated emission of the converged charged particle beam and scanning the beam in a predetermined region of the surface of the sample a plurality of times; a brightness gradation setting part that sets brightness gradation of the image from information on the number of pulses counted with the pulse count part; and an image formation part that forms an image using the information on the number of pulses by each position of the plurality of frames counted with the pulse count part and the information on the brightness gradation of the image set with the brightness gradation setting part.

12 . The image processing apparatus according to cl

Assignees

• Hitachi High Tech Corp

Inventors

• Ikeda Kazuki
• Li Wen
• Kawano Hajime
• Takahashi Hiroyuki
• Suzuki Makoto

Classifications

• H01J2237/2817

  Pattern inspection · CPC title

• H01J37/244

  Detectors; Associated components or circuits therefor · CPC title

• H01J2237/221

  Image processing · CPC title

• H01J37/222 Primary

  Image processing arrangements associated with the tube · CPC title

• H01J2237/2448

  Secondary particle detectors · CPC title