semi合集-English.pdf - 第5212页
SEMI M38-1104 © SEMI 1999, 2004 11 A1-5.2 Maintaining Inscription Utility — The angle o f the new inscription shall be provided to the customer by the supplier so that the to ol used to read the in scriptions can be adju…
SEMI M38-1104 © SEMI 1999, 2004 10
APPENDIX 1
SPECIFICATION FOR MULTIPLE LASER MARKING (RE-INSCRIPTION)
OF 300 mm POLISHED SILICON RECLAIMED WAFERS
NOTICE: The material in this appendix is an official part of SEMI M38 and was approved by full letter ballot
procedures on August 16, 2004.
A1-1 Purpose
A1-1.1 Silicon wafers are often subjected to reclaim
processes, in order to improve manufacturing efficiency
in device production. This process can remove
significant material from the marked surface of a 300
mm wafer. This can lead to reduced dot diameter for
marks with “v”-shaped profile, to the point that the
mark no longer meets the requirements of SEMI T7.
This can compromise the mark’s readability.
A1-1.2 This specification is intended to identify
locations on the back surface of 300 mm reclaimed
silicon wafers for re-inscribing the SEMI T7 and
optionally the OCR (according to SEMI M1.15) laser
marks in order to maintain traceability after multiple
reclaims.
A1-2 Scope
A1-2.1 This specification defines the spatial
relationships for back surface marking of reclaimable or
reclaimed notched, double-side polished 300 mm
wafers of silicon with pre-existing manufacturers’
marks which comply with SEMI M1.15.
A1-2.2 Although this specification does not specify the
marking equipment or techniques that may be
employed when complying with its requirements, it is
required that the symbols be a “hard mark” obtained by
laser scribing individual dots with diameter as specified
in SEMI T7.
NOTICE: This standard does not purport to address
safety issues, if any, associated with its use. It is the
responsibility of the users of this standard to establish
appropriate safety and health practices and determine
the applicability of regulatory or other limitations prior
to use.
A1-3 Referenced Standards
A1-3.1 SEMI Standards
SEMI M1.15 — Standard for 300 mm Polished
Monocrystalline Silicon Wafers (notched)
SEMI T7 — Specification for Back Surface Marking of
Double-Side Polished Wafers with a Two-Dimensional
Matrix Code Symbol
NOTICE: Unless otherwise indicated, all documents
cited shall be the latest published versions.
A1-4 Ordering Information
A1-4.1 For 300 mm wafers that are to be re-inscribed
the following shall be specified on the purchase order:
A1-4.1.1 Whether the previous inscription is to be
obliterated, and the method for such obliteration,
A1-4.1.2 Content of re-inscribed field
Same as prior mark, or
New field content
A1-5 Requirements
A1-5.1 Location of the Laser Inscription
A1-5.1.1 The original reference point shall be located
148.95 mm 0.15 mm from the center of the wafer
along a radius at 5.0 0.1 counterclockwise from the
axis of the fiducial bisector.
A1-5.1.2
The first re-inscription shall be placed
counterclockwise to the original mark at the same
distance from the wafer center on a radius 10
counterclockwise from the original mark.
A1-5.1.3 Any subsequent re-inscription shall be placed
counterclockwise to the previous mark at the same
distance from the wafer center on a radius 10
counterclockwise from the previous mark.
A1-5.1.4 Consequently, the most recent re-inscription
is located on a radius an angle
degrees
counterclockwise from the fiducial bisector as follows
(see Figure A1-1):
1.00.100.5
n
(1)
where
n = the total number of re-inscriptions.
SEMI M38-1104 © SEMI 1999, 2004 11
A1-5.2 Maintaining Inscription Utility — The angle of the new inscription shall be provided to the customer by the
supplier so that the tool used to read the inscriptions can be adjusted to read the wafer ID at the new angle. Since it
is possible for a tool to be provided the wrong angle to read an inscription, as long as the information remains the
same as the prior inscription, errors can be minimized (read attempts at different angles).
5° + n × 10°
5°
15°
25°
5° + n × 10°
Figure A1-1
Locations of Original Inscription and Subsequent Re-inscriptions on Back Surface of
Notched 300 mm Diameter Reclaimed Wafer
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.