semi合集-English.pdf - 第5214页
SEMI M38-1104 © SEMI 1999, 2004 13 This requires completely ov erwriting each of these characters with a filled 5 × 9 character field (45 dots at “single density ”). It was suggested this be done at two ID ch aracter s (…
SEMI M38-1104 © SEMI 1999, 2004 12
RELATED INFORMATION 1
BACKGROUND INFORMATION FOR MULTIPLE LASER MARKING (RE-
INSCRIPTION) OF 300 mm POLISHED SILICON RECLAIMED WAFERS
NOTICE: This related information is not an official part of SEMI M38. It was developed by the International 300
mm Reclaim Remark Task Force during the development of the specification for multiple-laser marking of 300 mm
polished silicon reclaimed wafers. This related information was approved for publication by full letter ballot
procedures on August 16, 2004.
R1-1 Multiple Laser Making Issues
R1-1.1 Issues related to multiple laser marking of 300
mm silicon reclaimed wafers were explored at meetings
during SEMICON West in San Francisco in July 2002,
SEMICON Southwest in Austin in October 2002,
SEMICON Japan in Tokyo in December 2002 and a ½
day workshop during SEMICON Europa in Munich in
April 2003. Significant input from device makers,
wafer reclaimers, and equipment suppliers was
received.
R1-1.2 Four major issues emerged.
R1-2 When Is a Remark
Field Applied?
R1-2.1 This could be at each reclaim cycle, or when
the “first” mark is not readable at the reclaimer.
R1-2.2 Because the latter is a difficult matter, it was
decided to make this a decision of the purchaser.
R1-3 Where Should the Remark Field(s) Be
Located?
R1-3.1 A device manufacturer suggested that each new
remark field be located 10 counter clockwise (CCW)
from the previous mark field, and at the same radius.
R1-3.2 A wafer with two of more fields is
unambiguously identified as a reclaim wafer and the
“n” remarked fields it contains indicate the number of
reclaim cycles it has experienced, if it is remarked after
each use.
R1-4 What Is the Remark Field’s Content?
R1-4.1 Two scenarios are possible:
R1-4.1.1 Different from the Original Mark — For
example, retaining the ID # but changing the supplier
code from original to the reclaim supplier’s code. This
could confuse a device fab’s database when two
identical ID numbers appear in the database unless it
also includes the vendor code. Changing the ID
number does not necessarily avoid this problem.
R1-4.1.2 Same as the Original Mark — This simplifies
the remark coding. However, the is still the possibility
of confusing the device manufacturer’s database.
R1-4.2 It was decided to make this a decision of the
purchaser.
R1-5 How to “Disable” a Previous Mark Field?
R1-5.1 Disabling a mark field requires that a mark
field be modified or obliterated sufficiently to ensure
the reader reports a “no read.”
R1-5.2 It was decided to make both the requirement to
obliterate the previous mark and the method of
obliteration decisions of the purchaser.
R1-6 Mark Field Obliteration Comments.
R1-6.1 Obliterating an entire field may not be
necessary to make it unreadable. For the two mark
fields specified in SEMI M1.15, the following may
apply:
R1-6.1.1 Data Matrix Field
R1-6.1.1.1 Reliable reading of this field requires a
quiet zone (no surface disturbance) about four dots
wide (400 µm) around the field periphery. Filling the
quiet zone with dots insures that the Data Matrix mark
cannot be read.
R1-6.1.1.1.1 Surrounding the 8 row 32 column field
with a 4-dot border involves (8 + 32) 2 4 = 320
dots.
R1-6.1.1.1.2 A 3-dot border may work as well, and
requires 240 dots.
R1-6.1.1.2
Conversely, overwriting the field involves
8 32 = 306 dots.
R1-6.1.1.2.1 A difference of 100 µm (one dot) between
the positions of the overwrite field and original field
should still produce a “no read.”
R1-6.1.1.2.2 Some position difference results from the
marker’s wafer alignment system. The alignment
capability of deployed 300 mm markers is therefore a
consideration.
R1-6.2 Alphanumeric Field
R1-6.2.1 Obliterating one or more message characters
and one or more check sum characters should make the
mark unreadable by both camera and human readers.
SEMI M38-1104 © SEMI 1999, 2004 13
This requires completely overwriting each of these
characters with a filled 5 × 9 character field (45 dots at
“single density”). It was suggested this be done at two
ID characters (1 and 6 in the 12-character string) and
one check sum character (12).
R1-6.2.2 This overwriting involves 3 fields 45 dots =
135 dots.
R1-6.2.3 The alignment comments in Section R1-
6.1.1.2.2 also apply to these fields.
R1-7 Use of Remarked Reclaimed Wafers in
Device Fabrication
R1-7.1 This may involve two scenarios:
R1-7.1.1 Incoming Search
R1-7.1.2 Determine the “good” remark field location
(5 + [10 n]) degrees from the notch bisector for each
wafer and store that data in the factory database. Then
the manufacturing execution system commands a tool
handling that wafer to go to the appropriate field
location. This minimizes or eliminates throughput
effects.
NOTE 1: This requires variable read location capability (by
wafer rotation, for instance) on the tool.
R1-7.2 Local Tool Search
R1-7.2.1 When unable to read the original field, the
tool scans counterclockwise until it finds a readable
field. This cycle can adversely impact tool throughput.
NOTE 2: This requires
Variable read location capability and
“Smart” read, i.e., 3 levels, as follows:
Good read (this is the “right” field, so keep the
data),
Bad read (this is an obliterated field, go to
“next” location and try again), and
No read (no mark is present, search somewhere
else).
NOTICE: SEMI makes no warranties or
representations as to the suitability of the standards set
forth herein for any particular application. The
determination of the suitability of the standard is solely
the responsibility of the user. Users are cautioned to
refer to manufacturer's instructions, product labels,
product data sheets, and other relevant literature,
respecting any materials or equipment mentioned
herein. These standards are subject to change without
notice.
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Equipment and Materials International (SEMI) takes no
position respecting the validity of any patent rights or
copyrights asserted in connection with any items
mentioned in this standard. Users of this standard are
expressly advised that determination of any such patent
rights or copyrights, and the risk of infringement of
such rights are entirely their own responsibility.
Copyright by SEMI® (Semiconductor Equipment and Materials
International), 3081 Zanker Road, San Jose, CA 95134. Reproduction of
the contents in whole or in part is forbidden without express written
consent of SEMI.
SEMI M39-0999 © SEMI 19991
SEMI M39-0999
TEST METHOD FOR MEASURING RESISTIVITY AND HALL
COEFFICIENT AND DETERMINING HALL MOBILITY IN SEMI-
INSULATING GaAs SINGLE CRYSTALS
This test method was technically approved by the Global Compound Semiconductor Committee and is the
direct responsibility of the Japanese Compound Semiconductor Committee. Current edition approved by the
Japanese Regional Standards Committee on June 1, 1999. Initially available at www.semi.org August 1999;
to be published September 1999.
1 Purpose
1.1 The purpose of this document is to specify a meth-
od to measure resistivity and determine Hall mobility of
semi-insulating GaAs single crystals by the Van der
Pauw method. Especially, this document specifies a
simple and practical method for commercial semi-
insulating GaAs single crystals.
2 Scope
2.1 This test method covers a procedure for measuring
the resistivity and determining Hall mobility of semi-
insulating GaAs single crystals by the van der Pauw
method. This method requires a singly connected test
specimen without any isolated holes, of homogeneous
thickness and with a square shape. In this method,
contacts must be sufficiently small and located at the
corners of the specimen.
2.2 This standard may involve hazardous materials,
operation, and equipment. This standard does not
purport to address all of the safety problems associated
with its use. It is the responsibility of the user of this
standard to establish appropriate safety and health
practices and determine the applicability of regulatory
limitations prior to use.
3 Referenced Standards
3.1 ASTM Standards
F 76-73 Standard Method for Measuring Hall
Mobility and Hall Coefficient in Extrinsic
Semiconductor Single Crystals
F 76-86 Standard Test Methods for Measuring
Resistivity and Hall Coefficient and Determining Hall
Mobility in Single-Crystal Semiconductors
F 43-93 Standard Test Methods for Resistivity of
Semiconductor Materials
NOTE 1: As listed or revised, all documents cited shall be the
latest publications of adopted standards.
4 Terminology
NOTE 2: Many of the terms associated with this test method
can be found in ASTM Definitions F 76-86.
hall mobility the ratio of the magnitude of the Hall
coefficient to the resistivity; it is readily interpreted
only in a system with carriers of one charge type.
resistivity the ratio of the potential gradient parallel
to the current in the material to the current density. For
the purpose of this method, the resistivity shall always
be determined for the case of zero magnetic flux.
5 Summary of Test Method
5.1 In this method, the thickness of a specimen cut
from a semi-insulating GaAs single crystal is measured.
5.2 Ohmic contacts are formed on the specimen.
5.3 The temperature near the specimen is measured.
5.4 Hall-effect measurement is performed and data are
taken.
5.5 From the measured data, the resistivity and Hall
mobility are calculated and corrected for temperature.
6 Interferences
6.1 Light could cause an error due to photo-
conductivity, so the specimen must be placed in a dark
environment.
6.2 Temperature fluctuation gives significant error.
Specimen itself could be at higher temperature than the
environment if one does not take sufficient time after
soldering the contacts.
6.3 The current-voltage conditions must be ohmic.
6.4 The damaged layer due to the sawing must be
removed by etching the specimen, for example by using
mixture of sulfuric acid (H
2
SO
4
), hydrogen peroxide
(H
2
O
2
) and water (H
2
SO
4
:H
2
O
2
:H
2
O = 3:1:1).
7 Apparatus
7.1 Measurement of Specimen Thickness — Dial
gauge, micrometer, or electronic thickness gauge