Bsi bs cecc 00013 1985 (1999)

2 Definitions 2.1 SEM inspe tion lot a SEM inspection lot is d efined as a n mber of wafer of the same ty pe which are selected f om the same difusion, oxid tion and metal sation ru and

00013:1985

This Bri sh Stan ard, ha ing

b en pre ared u der the

directonof the Electronic

Comp nents Stan ards

Commi e , was published

u derthe authoriy of the

Bo rdofBSI an comes

into fecton

3 Aug ust1 8

© BSI1 -1 9

The folowing BSI references

relate to the work on this

The prep ration of this British Stand rd was undertaken b the Electronic

Components Stand rds Commit e , upon which the fol owing bodies were

represented:

Association of Control Man facturer TACMA ( BEAMA)

Association of Franchised Distributor of Electronic Components

British Industrial Measuring and Control App ratus Man facturer ’

Association

British Stand rds Society

Control and Automation Man facturer ’ Association ( BEAMA)

Dep rtment of Industry Computer Sy stems an Electronic

Dep rtment of Tra e

Electronic Components Industry Federation

Electronic Eng ine ring Association

Eng ine ring Eq uipment User ’ Association

Ministry of Defence

National S perv ising Inspectorate

Post Ofice

Scientific Instrument Man facturer ’ Association

Society of British Aerosp ce Comp nies Limited

Telecommu ication Eng ine ring and Man facturing Association ( TEMA)

Am endm ents is ued sinc publ cation

Amd No Date of is ue Comments

3.2.1 W afer sample selection f om a metal isation ru 2

Chart 1 — Sample selection fom non-g las iv ated d ev ices 10

Chart 2 — Sample selection fom g las iv ated d ev ices 1

Chart 3 — Sample selection fom g las iv ated d ev ices 1

Chart 4 — Sample selection fom g las iv ated d ev ices 13

Chart 5 — Sample selection fom g las iv ated

Chart 6 — Sample selection for multi lev el sy stems 15

National foreword

This British Stand ard has be n prep red u d er the d irection of the Electronic

Components Stand rds Commit e It is identical with CENELEC Electronic

Components Commit e ( CECC)0 013:19 4 “ Ha r monized system o qua liy

a ss s ment f r ele tr onic components: B a sic spe ifica tion: Sca nning ele tr on

micr os ope inspe ton o s micond ucto d ic ”

This stand rd is a harmoniz d specification within the CECC sy stem

Term inolog y and conventions The text of the CECC specification has be n

a prov ed as suita le for publ cation as a British Stand rd without d ev iation

Some terminolog y and certain conv entions are not identical with those used in

British Stand rds; at ention is drawn especialy to the folowing

The comma has be n used as a decimal marker In British Stand rds it is cur ent

practice to use a ful point on the b selne as the decimal marker

N T The last p rt ( beg in ing “an co ies”) of p rag ra h4 of the foreword is not a plica le for this

Bri sh Stan ard

A British Stand rd d oes not purport to includ e al the neces ary prov isions ofa

contract User of British Stand ard s are responsible for their cor ect a plcation

Compl anc with a British Standard does not ofitself confer imm unity

f om leg al o l g ations

Sum m ary of pag es

This d ocument comprises a f ont cov er, an inside font cov er, p g es i to iv ,

theCECC title p g e, p g ei , p g es1 to15 and a b ck cov er

This stand ard has be n up ated ( se copy right d te) and ma hav e ha

amend ments incorporated This wi l be indicated in the amendment ta le on the

inside f ont cov er

The CENELEC Electronic Components Commit e ( CECC) is composed of those member cou tries of the

European Commit e for Electrotech ical Stand rd ization ( CENELEC) who wish to take p rt in a

harmoniz d Sy stem for electronic components of as es ed q ual ty

The object of the Sy stem is to faci itate international tra e b the harmonization of the specifications and

q ual ty as es ment procedures for electronic components, and b the g rant of an international y recog niz d

Mark, or Certificate, of Conformity The components produced u der the Sy stem are thereb ac epted b

al member cou tries without further testing

This specification has be n formaly a prov ed b the CECC, and has be n prep red for those cou tries

taking p rt in the Sy stem who wish to is ue national harmoniz d specifications for SCANNING

ELECTRON MICROSCOPE INSPECTION OF SEMICONDUCTOR DICE It should be rea in

conju ction with the cur ent reg ulations for the CECC Sy stem

Pr face

This b sic specification was prep red b the ESA/SCCG It was sponsored a ministrativ ely b CECC W G5

who mad e not contribution to the tech ical contents

The text of this specification was cir ulated to the CECC for v oting in the document indicated below and

was a prov ed b the Presid ent of the CECC for publcation as a CECC Specification

1 Scope

1.1 General

This specification des ribes the equipment and proced ures to be used for the s anning electron mic os ope

( SEM) inspection of dis rete semiconductor dev ices and integ rated cir uits

W hen SEM inspection is pres ribed in a detai specification, it shal be used in conjunction with the

relev ant Appendix of the a propriate CECC g eneric specification,wherein the specific ac ept/reject c iteria

wi be pres ribed

1.2 Alternative standards

W here the config uration of a p rticular component is not in ac ord nce with the ex mples shown in this

specification or where cur ent in-house inspection drawing s or stand ards ( ac epted in the PID) are to be

used, it shal be the man facturer’s responsibi ty to obtain the formal interpretation f om the ONS, or its

d esig nated representativ e, of any dev iation

2 Definitions

2.1

SEM inspe tion lot

a SEM inspection lot is d efined as a n mber of wafer of the same ty pe which are selected f om the same

difusion, oxid tion and metal sation ru and f om which a defined n mber of wafer shal be ex mined

with the SEM

2.2

o ide steps

oxid e steps are defined as any sloped or a rupt chang e in thick es of si con ox ide, si con nitrid e and / or

any other insulating lay er on a semiconductor or integ rated cir uit

2.3

m ulti- level m etalisation system

a multi lev el metal sation sy stem consists of two or more lay er of metal or any other conductiv e material

which are sep rated fom each other b an insulating material

2.4

m ulti- la ered- m etal

multi lay ered -metal is d efined as two or more lay er of metal or any other cond uctiv e material used for

inter on ections that are not isolated fom each other b a g rown or d eposited insulating material

2.5

critical areas

c itical areas shal be de med to be those areas where, b v irtue of d esig n, an inc eased pos ibi ity of fai ure

is prob ble Such areas shal be clearly identified b the man facturer b the prov ision of an enlarg ed

photog ra h of the complete die

ex mples of c itical areas are:

— v ery smal d istances betwe n conductor

— v ery nar ow cond uctor

— v ery hig h and ste p oxide steps

— v ery smal contact windows

3 Requir ments

3.1 Equipm ent

3.1.1 Scanning ele t ron micr s ope

The s an ing electron mic os ope used for this inspection shal me t the folowing req uirements:

3.1.2 Conductive fi m deposition

There shal be a faci ity for the deposition of a conductiv e fi m ov er the sample dice b v apour d eposition or

sput ering , if required

3.2 Sam ple sele tion

3.2.1 Wafer sample s le tion f om a metal isation run

W afer sample selection shal be ma e after the metal isation proces in ac ord nce with Fig ure 2

Thewafer of more than one SEM inspection lot shal be placed in sep rate sections of the wafer-holder I

one SEM inspection lot has les wafer than there are places on the wafer-holder,the wafer shal be placed

sy mmetricaly fom the outsid e to the centre of the wafer-holder One wafer fom the ed g e an one nearest

the centre of the wafer-hold er shal be taken as samples

In case of smal SEM inspection lots, it is permis ible to break wafer an to place the pieces in the

desig nated sections of the wafer-hold er prov ided they are big enoug h for die selection ac ording to3.2.3

Up to die selection, the selected wafer shal be handled throug hout al proces ing steps in such a manner

that they retain their tracea i ty

3.2.2 Wafer sample s le tion f om a pr cured lot

Selection of wafer samples f om a procured lot shal be ma e as folows:

— Lot siz smal er than10 wafer

One wafer per metal isation ru to be selected at random

— Lot siz of10 wafer or more

Two wafer per metal sation run to be selected at rand om

3.2.3 Die sample s le t ion

From each wafer selected in ac ord ance with3.2.1 or3.2.2, thre dice shal be selected( 1) as in

Fig ure 3or( 2) as in Fig ure 4

3.2.3.1 Non-gla ssiva ted d evic s

Dice f om non-g las iv ated dev ices shal be selected and ex mined in ac ord nce with Chart1

3.2.3.2 Gla ssiva ted d evic s

For the selection of dice f om g las iv ated d ev ices, there are two pos ibi ities:

1) Selection after etching of the metal isation structure, but before g las iv ation:

— I SEM inspection lots consist of20 or more wafer , the selection and ex mination shal be in

ac ord nce with Chart2 The wafer f om which the dice are selected shal not be used for further

proces ing

— I SEM inspection lots consist of les than20 wafer , the sample dice ma be selected an ex mined

in ac ord ance with either Chart2 or3 W afer fom which seg ments are detached for dice selection

ma be used for further production

—Ma nification : X 50 to X 200 0

—Acceleration v oltag e : 1 kV to25kV

—The specimen hold er shal be so constructed that the specimen ma be ex mined throug h a ti t

ang le rang ing f om0° to7 ° ( se Fig ure 1)

—It shal be pos ible to rotate the specimen throug h3 0° ov er the ful rang e of tit ang le

—The chamber for the specimen shal be so constructed that a specimen measuring at

I, during the g las iv ation proces , the temperatures used are hig her than any temperature used

during the metal isation proces , min s5 °C, the u g las iv ated sample dice shal be ex osed , in a

suita le atmosphere ( nitrog en), to the temperature/time characteristic of the g las iv ation proces

2) Selection after g las iv ation:

Die samples shal be selected and ex mined in ac ord ance with Chart 4 and the g las iv ation shal be

etched awa without d amag ing the metal isation of the dice This can be done when etching awa the

g las iv ation fom the contact p d s of the dev ices

For procured wafer ( se 3.2.2), sample selection and ex mination shal be in ac ord nce with Chart5

3.2.3.3 Muli-level meta llsa tion systems

Each metal isation lay er shal be ev aluated b detaching a seg ment ( se Fig ure 4)f om the a propriate

wafer sample ( se Chart6) The selection of wafer and d ie samples an d ie ex mination shal be in

ac ord nce with Chart6 It is permit ed to use the remainder of the wafer sample fom which the seg ment

is d etached for further proces ing

I, after breaking any seg ment, the temperatures used for further proces ing of the wafer are hig her than

any temperature used during the metal sation proces , min s5 °C, the seg ments for each metal sation

lay er shal be ex osed , in a suita le atmosphere ( nitrog en), to the temperature/time characteristic of the

further proces ing

3.3 Die sam ple preparation

3.3.1 Deposition o a conduct ive fi m

To obtain the req uired resolution it ma be neces ary to coat the die samples with a conductiv e fi m ( for

ex mple g old, p la ium/ g old or carbon) W hen cov ering the edg es and sides of the die with this fi m, care

shal be taken to ensure g ood electrical contact betwe n the fi m and the SEM specimen hold er

3.3.2 Mounting on spe imen holder

The die shal be fit ed flat and wel -g rou d ed to the specimen holder The mou ting shal be done in such

a wa that contamination is red uced to a minimum I the die is mou ted b means of a cond uctiv e a hesiv e

or other conductiv e material, special care shal be taken not to obs ure features to be ex mined

3.4 Die sam ple ex m ination, g eneral requirem ents

3.4.1 G eneral

All four edg e directions shal be ex mined on each d ie for each ty pe of contact wind ow step an for each

ty pe of other oxide step ( The word “ oxid e” shal be interpreted as any insulating material used on the

semiconductor d ie, whether SiO

x, SiN

x,etc) A sing le window ( or other ty pe of oxide step) ma be v iewed if

metal sation cov er the entire window ( or other ty pe of oxid e step) extend ing up to and ov er each edg e an

onto the top of the oxide at each edg e Other windows ( or other ty pe of oxid e step) on the die shal be

ex mined to me t the requirement that al four directional edg es of each ty pe of wind ow ( or other ty pe of

oxide step) shal be ex mined on each die Viewing for g eneral metal sation d efects, such as pe l ng and

v oid ing shal be such as to prov ide for the best ex mination for those defects

3.4.2 Viewing angle

Specimens shal be v iewed at whatev er ang le is a propriate to ac urately as es the qual ty ofthe

metal sation Contact windows are normal y v iewed at an ang le of4 ° to6 ° Metal sation thick es ,

a hesion, an etching d efects are normaly v iewed at an ang le of6 ° or g reater

3.4.3 Viewing dire tion

Specimens shal be v iewed at whatev er direction is a propriate to ac urately as es the qual ty of the

metal sation This shal include lo king at metal sation at the edg es of contact wind ows and other ty pes

ofoxid e steps ( se 3.4.1) in directions that prov ide u sha owed v iews of each edg e This ma mean that

the v iewing ang le is perpendicular to an edg e, or in l ne with an edg e, or at some obl q ue ang le,whichev er

best resolv es any q uestion of defects at the oxide step

3.4.4 Magnificat ion

The mag nification rang es shal be betwe n X 50 0 andX 200 0 for ex mination of oxide steps and

betwe nX 10 0 andX60 0 for ex mination for g eneral metal sation d efects, such as pe lng and v oiding

W hen dice are subjected to reinspection, such reinspection shal be ac omplshed within the specified

mag nification rang e, but at any mag nification within that rang e that is d eemed a propriate

3.5 Die sam ple ex m ination, detai requirements

3.5.1 Dis ret e s miconduct or devic s

3.5.1.1 Oxid e steps

Inspect the metal sation at al ty pes of oxid e steps In the case of r and /or power transistor with

interdig itated or mesh structures, as a minimum, each b se-emit er stripe p ir on each en of each p t ern

an ev ery fourth b se-emit er stripe p ir within each p t ern shal be inspected Particular at ention shal

be directed to lateral etching defects an u der ut etching at b se and emit er oxid e steps.Documentation

shal be as specified in Section4

3.5.1.2 Gener a l meta llsa tion

Inspect al g eneral metal isation on each die for defects such as pe l ng and v oiding Document in

ac ord ance with Section4

3.5.2 Int egrated circuits

3.5.2.1 Oxid e steps

Inspect the metal sation at al ty pes of oxide steps Document in ac ord nce with Section4

3.5.2.2 Gener a l meta llsa tion

Inspect at least25 per ent of the g eneral metal isation on each die for d efects, such as pe lng or v oiding

Document in ac ord nce with Section4

3.5.3 Multi-lay ered-metal interconne t ion syst ems

Multi Lay ered -Metal is d efined as two or more lay er of metal or any other material used for

inter onnections that are not isolated f om each other b a g rown or d eposited insulating material

Theterm “ underly ing lay er” shal refer to any lay er below the top lay er of metal Each lay er of metal shal

be ex mined The princip l cur ent-car y ing lay er shal be ex mined with the SEM; the other lay er

( e.g b r ier or a hesion) ma be ex mined using either the SEM or an optical mic os ope, at the

man facturer’s option The g las iv ation ( if any ) and each suc es iv e lay er of metal shal be strip ed b

selectiv e etching with suita le reag ents, lay er b lay er, to ena le the ex mination of each lay er.Normal y

each suc es iv e lay er of metal wi l be strip ed in sequence to ex ose the next u d erly ing lay er for

ex mination It ma be impractical to remov e the diferent lay er on a sing le die, lay er b lay er In this

case, an ad ditional d ie ( dice) immed iately ad jacent on the slce to the orig inal die shal be strip ed to me t

the req uirement that al lay er shal be ex osed and ex mined Specimen ex mination shal be in

ac ord nce with3.5.1 or3.5.2 whichev er is a plca le

3.6 Spe im en after ex mination

No SEM-nspected specimen shal be used for further proces ing The specimens of each ac epted SEM

inspection lot shal be stored at the man facturer’s plant for a period of, at least,24 months.They shal be

delv ered to the ord erer upon req uest

3.7 Ac eptanc requirem ents

3.7.1 G eneral

Rejection of d ice shal be b sed upon lot proces oriented defects Rejection shal not be b sed upon

workmanship and other ty pe defects such as s ratches, smeared metal isation, to l ng marks, etc In the

ev ent that the presence of such defects obs ures the d etaied features being ex mined, an ad ditional die

shal be ex mined which is immed iately a jacent to the die with the obs ured metal sation

3.7.2 Single wafer ac eptanc basis

The metal isation on a sing le wafer shal be judg ed ac epta le only if al sample dice f om that wafer are