News Column

Patent Issued for Method of Aligning a Substrate

June 4, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent by the inventors Kim, Young-Seok (Suwon-si, KR); Peak, Jong-Sun (Hwaseong-si, KR), filed on September 20, 2011, was published online on May 20, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8730475 is assigned to Samsung Electronics Co., Ltd. (KR).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The present invention relates generally to a method of aligning a substrate.

"Generally, various semiconductor fabricating processes may be performed on a semiconductor substrate to form a plurality of patterns. In order to identify whether the patterns may be normal or not, a process for inspecting the patterns may be performed between the semiconductor fabrication processes.

"In order to inspect the patterns, it may be necessary to perform a process for accurately aligning the semiconductor substrate. The aligning process may include a process for moving the semiconductor substrate to align an alignment mark on a scribe lane of the semiconductor substrate with a reference coordinate predetermined set in an alignment apparatus.

"According to a conventional aligning method, a first alignment mark in a first shot region may be identified. The identified alignment mark may then be aligned with a predetermined first coordinate. A second alignment mark in a second shot region, which may be located from the first shot region in an x-direction, may be identified. The identified second alignment mark may then be aligned with a predetermined second coordinate. A third alignment mark in a third shot region, which may be located from the first shot region in a y-direction, may be identified. The identified third alignment mark may then be aligned with a predetermined third coordinate. That is, only a single alignment mark in each of the shot regions may be aligned with the predetermined coordinate.

"Meanwhile, when the alignment mark may not be identified, the alignment apparatus may determine the semiconductor substrate to be abnormal. The abnormal semiconductor substrate may be unloaded from the alignment apparatus. New alignment recipes may be set in the alignment apparatus. The above-mentioned aligning processes may then be performed on other semiconductor substrates to align the semiconductor substrates.

"Although the alignment mark may be aligned with the predetermined coordinate, the alignment apparatus may not identify the aligned alignment mark due to an obscure image of the aligned alignment mark. According to the conventional method, the alignment apparatus may determine the semiconductor substrate having the aligned alignment mark. As a result, an alignment time of the alignment process may be too long. This may cause a low yield of semiconductor devices.

"Further, only one allowable alignment score may be set as a determination standard of an alignment failure. That is, when an alignment score measured from an identified alignment mark of a semiconductor substrate may be above the allowable alignment score, the semiconductor substrate may be determined to be normally aligned. In contrast, when an alignment score measured from an identified mark of a semiconductor substrate may be below the allowable alignment score, the semiconductor substrate may be determined to be abnormally aligned. Therefore, although a semiconductor substrate may be accurately aligned, an alignment score of an alignment mark in the accurately aligned semiconductor substrate may be below the allowable alignment score due to an obscure image of the alignment mark. As a result, the accurately aligned semiconductor substrate may be determined to be abnormal.

"Further, according to a related aligning method, the alignment marks in the first shot region may be identified in an order substantially the same as that in the first shot region. For example, when a third alignment mark in the first region may be identified, the third alignment mark in the second region may be identified after the first alignment mark and the second alignment mark may not be identified, although a possibility for identifying the third alignment mark in the second shot region may be higher than that for identifying the first alignment mark and the second alignment mark.

"Therefore, a time for identifying the alignment mark may be increased. As a result, a time for aligning the substrate may also be increased, so that a yield of semiconductor devices may be low."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "Some embodiments of the present invention provide a method of rapidly aligning a substrate.

"In a method of aligning a substrate in accordance with an embodiment of the present invention, a first alignment mark and a second alignment mark in a first shot region on the substrate may be sequentially identified. The substrate may be primarily aligned using any one of the identified first and second alignment marks. A used alignment mark and an unused alignment mark during the primary alignment process of the first alignment mark and the second alignment mark in a second shot region on the substrate may be sequentially identified. The substrate may be secondarily aligned using any one of the identified used and unused alignment marks during the primary alignment process.

"According to some embodiments of the present invention, the first alignment mark may have brightness greater than that of the second alignment mark.

"According to some embodiments of the present invention, the method may further include identifying a used alignment mark and an unused alignment mark during the secondary alignment process of the first alignment mark and the second alignment mark in the second shot region on the substrate may be sequentially identified, and tertiarily aligning the substrate using any one of the identified used and unused alignment marks during the secondary alignment process. The second shot region may be located at a second position in a first direction from the first shot region. The third shot region may be located at a third position in a second direction substantially perpendicular to the first direction.

"According to some embodiments of the present invention, the method may further include displaying alignment scores that may represent alignment states of the first alignment mark and the second alignment mark.

"According to some embodiments of the present invention, the method may further include setting an allowable alignment score that may be used for determining non-identifications of the first alignment mark and the second alignment mark, and setting a final allowable alignment score, which may be used for finally determining non-identifications of the first alignment mark and the second alignment mark, lower than the allowable alignment score. Setting the final allowable alignment score may include changing alignment values in a descending order from the allowable alignment score to the final allowable alignment score.

"According to some embodiments of the present invention, the method may further include correcting a height of the substrate.

"According to some embodiments of the present invention, the first alignment mark and the second alignment mark may have substantially the same shape. Alternatively, the first alignment mark and the second alignment mark may have different shapes.

"In a method of aligning a substrate in accordance with other embodiments of the present invention, a first alignment mark, a second alignment mark, a third alignment mark and a fourth alignment mark on a first shot region of a substrate may be sequentially identified. The first alignment mark may have a first brightness. The second alignment mark may have a second brightness less than the first brightness. The third alignment mark may have a third brightness less than the second brightness. The fourth alignment mark may have a fourth brightness less than the third brightness. The substrate may be primarily aligned using any one of the identified first, second, third, and fourth alignment marks. A used alignment mark during the primary alignment process of the first alignment mark, the second alignment mark, the third alignment mark and the fourth alignment mark in a second shot region on the substrate may be identified. When the used alignment mark may not be identified, unused alignment marks during the primary alignment process may be sequentially identified in order of the brightness thereof. The substrate may be secondarily aligned using any one of the identified unused alignment marks during the primary alignment process. A used alignment mark during the second alignment process of the first alignment mark, the second alignment mark, the third alignment mark and the fourth alignment mark in a third shot region on the substrate may be identified. When the used alignment mark may not be identified, unused alignment marks during the second alignment process may be sequentially identified in order of the brightness thereof. The substrate may be tertiarily aligned using any one of the identified unused alignment marks during the secondary alignment process.

"According to some embodiments of the present invention, the method may further include displaying alignment scores that may represent alignment states of the first alignment mark, the second alignment mark, the third alignment mark and the fourth alignment mark.

"According to some embodiments of the present invention, the method may further include setting an allowable alignment score that may be used for determining non-identifications of the first alignment mark, the second alignment mark, the third alignment mark and the fourth alignment mark, and setting a final allowable alignment score, which may be used for finally determining non-identifications of the first alignment mark, the second alignment mark, the third alignment mark and the fourth alignment mark, lower than the allowable alignment score. Setting the final allowable alignment score may include changing alignment values in a descending order from the allowable alignment score to the final allowable alignment score.

"According to embodiments of the present invention, an identified alignment mark in the first shot region may be first identified in the second shot region, so that a time for identifying the alignment mark may be reduced. Further, when the identified alignment mark in the first shot region may not be identified in the second shot region, the unused alignment marks may be sequentially identified in order of the brightness, so that the time for identifying the alignment mark may be more reduced. As a result, a time for aligning the substrate may be decreased, so that a yield of semiconductor devices may be improved."

URL and more information on this patent, see: Kim, Young-Seok; Peak, Jong-Sun. Method of Aligning a Substrate. U.S. Patent Number 8730475, filed September 20, 2011, and published online on May 20, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=61&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3010&f=G&l=50&co1=AND&d=PTXT&s1=20140520.PD.&OS=ISD/20140520&RS=ISD/20140520

Keywords for this news article include: Semiconductor, Samsung Electronics Co. Ltd..

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Electronics Newsweekly


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters