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SEMI T7-0303 © SEMI 1997, 2003 2 4.1.10 dat a matrix c ode symbol — a two-dim ensional array of squ are cells arranged in co ntiguous rows and columns. In cert ain ECC200 sym bols, data regions are separated by al ignmen…

SEMI T7-0303 © SEMI 1997, 2003 1

SEMI T7-0303

SPECIFICATION FOR BACK SURFACE MARKING OF DOUBLE-SIDE

POLISHED WAFERS WITH A TWO-DIMENSIONAL MATRIX CODE

SYMBOL

This specification was technically approved by the Global Traceability Committee and is the direct

responsibility of the North American Traceability Committee. Current edition approved by the North

American Traceability Committee on November 22, 2002. Initially available at www.semi.org January 2003;

to be published March 2003. Originally published in 1997; previously published November 2002.

1 Purpose

1.1 This specification is intended to provide a marking

symbology that can be used to mark silicon wafers with

no intrusion into the fixed quality area of the wafer.

2 Scope

2.1 This specification defines the geometric and spatial

relationships and content (including the error checking

and correcting code) of a rectangular two-dimensional

(2-D), machine-readable, binary data matrix code

symbol for back surface marking of notched, double-

side polished wafers of silicon which comply with

SEMI M1.15, and other materials with diameters of 300

mm and larger.

2.2 Although this specification does not specify the

marking techniques that may be employed when

complying with its requirements, it is assumed that the

symbol will be obtained by laser scribing individual

dots.

2.3 The matrix code is applicable to a broad range of

wafer products including epitaxial wafers, SOI wafers,

and unpatterned or patterned polished wafers. The

format and algorithms of this code are based on two-

dimensional symbology specified in ISO/IEC 16022.

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 health practices and determine the

applicability or regulatory limitations prior to use.

3 Referenced Standards

3.1 SEMI Standards

SEMI AUX001 — List of Vendor Identification Codes

SEMI M1.15 — Standard for 300 mm Polished

Monocrystalline Silicon Wafers (Notched)

SEMI M12 — Specification for Serial Alphanumeric

Marking of Silicon Wafers

3.2 ISO/IEC Standard

ISO/IEC 16022 — International Symbology

Specification – Data Matrix

NOTICE: Unless otherwise indicated, all documents

cited shall be the latest published versions.

4 Terminology

4.1 Definitions

4.1.1 alignment bar, of a data matrix code symbol — a

solid line of contiguous filled cells abutting a line of

alternately filled and empty cells [ISO/IEC 16022].

4.1.2 binary values — a dot in the wafer surface

indicates the binary value 1. The absence of a dot, or a

smooth surface surrounding a cell center point indicates

the binary value 0.

4.1.3 border column — the outermost column of a data

matrix code symbol. This column is a portion of the

finder pattern.

4.1.4 border row — the outermost row of a data matrix

code symbol. This row is a portion of the finder pattern.

4.1.5 cell, of a data matrix code symbol — the area

within which a dot may be placed to indicate a binary

value.

4.1.6 cell center point, of an array — the point at

which the centerline of a row intersects the centerline of

a column.

4.1.7 cell spacing, of an array — the (equal) vertical or

horizontal distance between the cell center points of

contiguous cells.

4.1.8 center line, of a row or column — the line

positioned parallel to, and spaced equally between, the

boundary lines of the row or column.

4.1.9 central area, of a cell — the area enclosed by a

circle centered at the cell center point; used by code

readers to sense the binary value of the cell.

1 International Organization for Standardization, ISO Central

Secretariat, 1, rue de Varembé, Case postale 56, CH-1211 Geneva 20,

Switzerland. Telephone: 41.22.749.01.11; Fax: 41.22.733.34.30

Website: http://www.iso.ch

SEMI T7-0303 © SEMI 1997, 2003 2

4.1.10 data matrix code symbol — a two-dimensional

array of square cells arranged in contiguous rows and

columns. In certain ECC200 symbols, data regions are

separated by alignment patterns. The data region is

surrounded by a finder pattern [ISO/IEC 16022].

4.1.11 dot — a localized region with a reflectance

which differs from that of the surrounding surface.

NOTE 1: To assure reading efficiency, a minimum contrast

of 30% is required between the reflectance value of a dot and

the surrounding wafer surface. Various densitometers can

provide such measurements nondestructively.

4.1.12 dot misalignment, within a cell — the distance

between the physical center point of a dot and the cell

center point.

4.1.13 finder pattern, of a data matrix code symbol —

a perimeter to the data region. Two adjacent sides

contain dots in every cell; these are used primarily to

define physical size, orientation and symbol distortion.

The two opposite sides are made up of cells containing

dots in alternate cells [ISO/IEC 16022].

4.1.14 reference point, of a data matrix code symbol —

the physical center point of a corner cell common to the

primary border row and the solid line of the alignment

bar, used to identify the physical location of the symbol

on the object being marked with the symbol.

NOTE 2: The reference point is at a fixed location on the

object. Different cells may be chosen as the reference point

depending on the desired orientation of the symbol on the

object and the size variability of the symbol. The particular

cell to be used as the reference point must be specified for

each application.

5 Requirements

5.1 Shape and Size of the Data Matrix Code Symbol

5.1.1 Data Matrix Code Symbol Dimensions

5.1.1.1 Each rectangular matrix code symbol shall be

composed of an array of 8 rows and 32 columns with an

alignment bar as defined in ISO/IEC ISS 16022.

5.1.1.2 Cell spacing shall be 125 µ m, center to center.

5.1.2 Dot Size — The nominal shape of the dot

produced in the matrix may be circular or square. Its

diameter or edge length (after polishing) shall be 100

µ m + 10 µ m – 20 µ m.

5.1.3 Border Rows and Columns

5.1.3.1 One border row and one border column shall

contain a dot in each cell. These are identified as the

primary border row and the primary border column.

These are used by the code reader to determine the

orientation of the matrix.

5.1.3.2 The opposing (secondary) border row and

column shall contain dots in alternating cells.

5.1.3.3 For these rectangular matrix code symbols, the

reference point of the symbol shall be the physical

centerpoint of the cell common to the primary border

row and the center alignment bar.

5.1.4 The maximum dot misalignment within a cell is

15 µ m. This ensures that a minimum size dot covers a

cell central area of radius 25 µ m.

5.1.5 Adjacent dots shall not touch.

5.2 Content of the Data Matrix Code Symbol

5.2.1 Each rectangular matrix code symbol shall

contain 10 message characters, together with the error

checking and correcting (ECC200) code characters,

encoded in accordance with ISO/IEC ISS 16022.

5.2.2 The message characters may include the

following: A–Z, 0–9, and dash (–). These characters

constitute the SEMI OCR Character Set except for the

period (.); this is the same character set specified in

SEMI M12. These characters are also included in the

set designated as “primarily upper case alphanumeric”

in ISO/IEC 16022, in Table 5 and Annexe J. The ten

message characters shall contain two elements:

a. a vendor-assigned 8-character wafer identification

code, followed by

b. a 2-character vendor identification code (see SEMI

AUX001).

5.3 Location of the Data Matrix Code Symbol

5.3.1 With the wafer positioned back surface up and

with the primary fiducial (notch) toward the operator,

the origin of the data matrix code symbol shall be

located as specified below.

5.3.1.1 The 8 row × 32 column rectangular 2-D matrix

code symbol shall be placed entirely outside a fixed

quality area (FQA) with a nominal edge exclusion of 3

mm. The reference point shall be located 148.95 ± 0.15

mm from the center of the wafer, along a radius 5.0 ±

0.1° counterclockwise from the axis of the notch

fiducial bisector.

5.3.2 The primary row of the matrix code symbol shall

be placed toward the periphery of the wafer.

32 cells per row

C1 C2

8 cells per

column

Nominal Dimensions (mm)

R1 = 3.875

C1 = 0.875

R2 = 4.000

C2 = 1.000

Figure 2

Data Matrix Field Dimensions

ECC200 - 8 rows × 32 columns

To Wafer Cente

Dimensions in millimeters are o

center to center of dots

Figure 3

Data Matrix Code Fields

ECC200 - 8 rows × 32 columns