SEMI C34-0699 SPECIFICATION AND GUIDELINE FOR MIXED ACID ETCHANTS.pdf

SEMI C34-0699
SPECIFICATON AND GUIDELINE FOR MKED ACID ETCHANTS
This spccification and this guideline wcrc technically approvcd by the Global Process Chemicals Committcc
Id arc the dircct responsibility of the North Amcrican Proccss Chcmicals Committce. Currcnt edition
approved by the North American Regional Standards Committee on April 23, 1999. Initially available on
SEMI Onlinc May 1999; to be published Junc 1999. This documcnt replaces SEMI C2. I and C7.19 in thcir
cntircty. Originally published in 1981 and 1995 rcspcctivcly
49% hydrofluoric acid, and glacial acetic acid
1 Purpose
1. I The purpose of this document is to standardize
requirements for mixed acid etchants used in the
7 Tolerances
Nitric Acid
1%(016mqg
support those standards. Test methods have been shown
Hydrofluoric Acid
士0.5%(士0.25mcqg)
to give statistically valid results. This document also
provides guidelines for grades of mixed acid etchants
Acetic Acid
±10%(は017mrqg
for which a need has been identified In the case of the
guidelines, the test methods may not have been 8 Requirements
statistically validated yet
8.1 The requirements for mixed acid etchants for
Grade I and Tier A are listed in Table 1
2 Scope
2.1 The scope of this document is all grades of mixe
9 Grade 1 Procedures
acid etchants used in the semiconductor industry
Accurately weigh a sample
containing 30 to 40 milliequivalents of acidity in a
3 Limitations
lyethylene weighing bottle. Transfer with water to a
3.1 None
polyethylene beaker and diln
100 ML. Add 10 drops
4 Referenced Documents
phenolphthalein indicator solution and titrate with 1 N
SEMI CI- Specifications for Reagents
standardized sodium hydroxide to a faint pink end
point. Calculate the total acidity (A
SEMI C2 -Specifications for Etchants
otal Acidity( mzy)
ML X N of NAOH
eight of sample(e
5 Terminology
mired acid etchant
9.2 Hydrofluoric Acid-a(
eigh a sample
any combination of nitric
hydrofluoric, and acetic acids with the
containing 0.3 to 0.5 g of hydrofluoric acid in a
composition expressed in terms of volumes of 70%
polyethylene beaker and dilute to approximately 100
nitric acid, 49% hydrofluoric acid, and glacial acetic ml. Add 10 drops of phenolphthalein indicator solution
acid, respectively. In the expression, all the relative
volumes shall be reduced to a ratio of
and titrate with 1 N or stronger sodium hydroxide
Thole numbers. For example. a 3: 1: 2 mixed acid
olution to a faint pink endpoint. Add 25 ml of Acetate
etchant would imply a mixture of 3 volumes of 70%
Buffer for Hydrofluoric Acid Determination and I g of
nitric acid, I volume of 49% hydrofluoric acid
Cyanine R
volumes of glacial acetic acid. If a component is absent continuously by magnetic stirring and titrate with
its relative volume shall be taken as zero. For example
standardized aluminum chloride solution to a pink
a 3: 1: 0 mixed acid etchant would imply that no acetic
purple endpoint
acid 1s present
IL X HF fa
ACl、soln
W Hydrofluoric Acid
Wcight of samplc(g
6 Composition
6.1 The content of each of the com ponents of a mixed 9.3 Nitric Acid
g
h
mple
containing 0.9 to