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SEMI MF1809-0704 © SEMI 2003, 2004 12 RELATED INFORMATION 2 GUIDELINES FOR SPONSORS OF ADDITIONAL ETCHING SOLUTIONS NOTICE: This related in formation is not an offi cial part of SEMI MF1809. It was develo ped during the …

SEMI MF1809-0704 © SEMI 2003, 2004 11

RELATED INFORMATION 1

RELATIONSHIPS BETWEEN SEMI MF1809 AND JIS H-0609

NOTICE: This related information is not an official part of SEMI MF1809. It was developed by the task

force during the revision of the document in 2003. This related information was approved for publication

by full letter ballot on April 22, 2004.

R1-1 Both this guide and test method JIS H-0609

identify etching solutions for use in delineating

structural defects in silicon. As indicated in 2.3, this

guide is intended to be used with other practices and

test methods while JIS H-0609 covers the entire

delineation and counting process.

R1-2 JIS H-0609 contains sections on terminology,

sample preparation, including thermal oxidation, selec-

tion of etchants, etching procedures, measurement loca-

tions, and measurement methods for various crystalline

defects.

R1-2.1 The definitions of the various crystal defects

are generally similar to those in SEMI MF1241 with

only minor differences in emphasis.

R1-2.2 Sample preparation and etching procedures are

similar in most respects to the procedures in SEMI

MF1725, SEMI MF1726, and (for thermal oxidation)

SEMI MF1727. The minor differences in definitions

are not considered to be technically significant.

R1-2.3 JIS H-0609 covers only non-chromic etching

solutions that differ from those covered in this guide.

Tables R1-1 and R1-2 list the etching solutions

discussed in JIS H-0609. Detailed discussions of the

suitability of the various etching solutions and

microphotographs of exposed crystal defects are

provided in JIS H-0609, similarly to the manner in

which similar information is provided in this guide.

Although JIS H-0609 does not cover the use of chrome-

containing etching solutions, it does contain com-

parisons with the etch rates of several chrome-con-

taining etching solutions, including Secco, Wright, and

Sirtl etches (see Section 9 for references to these

etching solutions).

R1-2.4 JIS H-0609 covers a variety of different mea-

suring locations and counting procedures for various

different crystal defects, unlike SEMI MF1810, which

describes only a method for counting etch pits in a

specified pattern. Visual inspection of some defect

types is recommended by JIS H-0609; such visual

inspection is also covered in SEMI MF523. JIS H-0609

includes a discussion of observation of denuded zone,

but because of the variety of technologies in place for

this aspect, no standardized measurement method is

defined.

Table R1-1 Composition of preferential etching solutions (I) (volume ratio) from JIS H-0609

Etching Solution Hydrofluoric Acid Nitric Acid Acetic Acid Water

A 1 12.7 3 3.7

B 1 12.7 3 5.7

C 1 12.7 1 6.7

D 2 12.7 2 6.7

Table R1-2 Composition of preferential etching solutions (II) (volume ratio) from JIS H-0609

Applicable Wafer

Dopant, Crystal Surface

Etching

Solution

HF HNO

COOH H

Additive Reagent Name:

Concentration

E(Note 1) 1 2.5 — 10.5 AgNO

: 0.005 mol/L(Note 2)

F(Note 1) 3 5.1 — 7.9

B (100)

G 1 12.7 — 6.3

Sb (100) H 2 5.9 2 6.1 KI: 0.1~ 0.5 g/L(Note 3)

Sb (111) I 2 6.8 2 6.2 KI: 0.1~ 0.5 g/L(Note 3)

NOTE 1: E and F Etches form a stain film. The stain film can be removed by rinsing the stained wafer and dipping it into B Etch for 5~ 10 s.

NOTE 2: By mixing 8 mL of 0.005 mol/L silver nitrate (AgNO

) aqueous etching solution into E Etch, the starting time of the reaction can be

advanced.

NOTE 3: By mixing 0.1~ 0.5 g/L potassium iodide (KI) to H and I Etches, stain film formation can be suppressed.

SEMI MF1809-0704 © SEMI 2003, 2004 12

RELATED INFORMATION 2

GUIDELINES FOR SPONSORS OF ADDITIONAL ETCHING

SOLUTIONS

NOTICE: This related information is not an official part of SEMI MF1809. It was developed during the original

development of the document. This related information was approved for publication by full letter ballot on April

22, 2004.

R2-1 A sponsor of additional etching solutions shall

submit tabular information and pictures of etched defect

examples (see Figures 1–32) to the SEMI staff engineer

or coordinator for the Silicon Wafer Committee as

follows:

R2-1.1 A preferential etching solution submitted as an

addition to this guide must be sponsored by an

individual willing to supply information for Tables 1

and 3 or Tables 2 and 4 as appropriate for the type of

etching solution.

R2-1.2 Defect pictures, approximately 2 by 3 in. (50

mm by 75 mm) in size, demonstrating the applications

of the solution shall include the following descriptive

information:

• Image magnification (approximately 400×

preferred),

• Surface removal during etch (in micrometers),

• Relevant sample history (that is, thermal cycle

type, resistivity, agitation, etc.), and

R2-1.3 Images submitted should include OISF' s and

dislocations for (100) and (111) surfaces and, in

addition as available, shallow pits (s-pits), hillocks,

artifacts, and epitaxial defects.

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.

By publication of this standard, Semiconductor

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.

International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o

the contents in whole or in part is forbidden without express written

consent of SEMI.

SEMI MF1810-0304 © SEMI 2003, 2004 1

SEMI MF1810-0304

TEST METHOD FOR COUNTING PREFERENTIALLY ETCHED OR

DECORATED SURFACE DEFECTS IN SILICON WAFERS

This test method was technically approved by the Global Silicon Wafer Committee and is the direct

responsibility of the North American Silicon Wafer Committee. Current edition approved for publication by

the North American Regional Standards Committee on December 4, 2003. Initially available at

www.semi.org February 2004; to be published March 2004. Originally published by ASTM International as

ASTM F 1810-97. Last previous edition SEMI MF1810-97 (Reapproved 2002).

1 Purpose

1.1 Defects on or in silicon wafers may adversely

affect device performance and yield.

1.2 Crystal defect analysis is a useful technique in

troubleshooting device process problems. The type,

location, and density of defects counted by this test

method may be related to the crystal growth process,

surface preparation, contamination, or thermal history

of the wafer.

1.3 This test method is suitable for acceptance testing

when used with referenced standards.

2 Scope

2.1 This test method describes the technique to count

the density of surface defects in silicon wafers by

microscopic analysis.

NOTE 1: Practical use of a defect counting method requires

an assumption be made that defects are randomly distributed

on the surface. If this assumption is not met, the accuracy and

precision of this test method will be diminished.

2.2 Application of this test method is limited to

specimens that have discrete, identifiable artifacts on

the surface of the silicon sample. Typical samples have

been preferentially etched according to SEMI MF1809

or epitaxially deposited, forming defects in a silicon

layer structure.

2.3 Wafer thickness and diameter for this test method

is limited only by the range of microscope stage

motions available.

2.4 This test method is applicable to silicon wafers

with defect density between 0.01 and 10,000 defects per

NOTE 2: The commercially significant defect density range

is between 0.01 to 10 defects per cm

, but this test method

extends to higher defect levels due to the improved statistical

sampling obtained with higher counts.

NOTICE: This standard does not purport to address

safety issues, if any, 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 or other limitations prior

to use.

3 Limitations

3.1 Improper identification of defects is possible

during the counting process.

3.1.1 Contamination not removed by cleaning

procedures or deposited following cleaning, may

become visible after preferential etching.

3.1.2 Insufficient agitation during the preferential

etching process may cause artifacts that may be

mistaken as crystallographic defects.

3.2 The accuracy of the defect density calculation is

directly affected by calibration of the area of the

microscope field of view.

3.3 The defect density determined by this test method

requires an assumption be made that defects are

randomly distributed on the surface. Nonuniform

patterns of defects alter the defect density measurement

by their size and location.

3.4 Multiple scan patterns intersect at the center of the

wafer. If a defect is found at this single, common point,

it is counted more than once and thus alters the

accuracy of the count.

4 Referenced Standards

4.1 SEMI Standards

SEMI M1 — Specifications for Polished Monocrystal-

line Silicon Wafers

SEMI MF1241 — Terminology of Silicon Technology

SEMI MF1725 — Practice for Analysis of Crystal-

lographic Perfection of Silicon Ingots

SEMI MF1726 — Practice for Analysis of Crystal-

lographic Perfection of Silicon Wafers

SEMI MF1727 — Practice for Detection of Oxidation

Induced Defects in Polished Silicon Wafers

SEMI MF1809 — Guide for Selection and Use of

Etching Solutions to Delineate Structural Defects in

Silicon