Many industries are still just coming to grips with the phaseout of long-used popu- lar cleaners. The printed circuit board (PCB) industry assembled a cleaner evaluation group as soon as phaseouts were announced; an Institute for Interconnecting and Packag- ing Electronic Circuits (IPC) task group had been working on a program for evaluating PCB surface cleanliness since December, 1987.

Discussions of alternative cleaners began in March, 1988 when Dr. Stephen Andersen, then chief of the Technology and Economics Branch of the Environmental Protection Agency’s (EPA) Global Change Division, called together an “Ad Hoc Solvents Group” to dis- cuss replacing CFC-113.

The IPC and EPA soon merged their efforts with the Department of Defense to form the Joint EPA/DOD/lndustry Ad Hoc Solvents Working Group, to develop a procedure for evaluating alternative materials that would re- duce use of CFCs to clean electronic assem- blies. The Ad Hoc Working Group is large, including:

Two associations. 14 government and academic groups. 14 major defense contractors and eight commercial manufacturers.

Circuit Board Ind ____

Evaluates Cle ____

Test boards pass through a semi- aqueous cleaner in accordance with strict procedures established in IPC’s cleanliness test program.

18 solvent and alternative cleaner producers. 14 flux and cleaning equipment manufac- turers. From the beginning, the Ad Hoc Working

Group realized that military specifications would be the biggest obstacle to changing cleaners. As much as 50 percent of all CFC usage for cleaning circuit boards had been specified by the military through various as- sembly documents. The Ad Hoc Working Group needed the involvement and coopera- tion of the armed services to seek changes in military specifications.

Three-phase Procedure A three-phase program was conceived to

supervise cleaner evaluatinns. Phase 1: Create a cleanliness benchmark

test for CFC-113 solvent currently used. Phase 2: Apply the same test criteria to

evaluate alternative cleaners, to identify those “as good as” or “better than” the CFC-113 solvent benchmark.

Phase 3: Study other options such as no-clean fluxes, water-soluble fluxes and inert atmosphere soldering.

Test Vehicle For scientific uniformity and fairness to all

firms offering cleaners, an industry-standard assembly (IPC B-36) was designed using both through-hole and surface-mount technolo- gies. The board was made of four-inch square, ,060-inch thick, FR-4 laminate divided into four quadrants: two with VIA holes and two without to mimic through-hole technology.

Two quadrants were assembled with two 68 I/O leadless chip carriers and standard industry fluxes. The board components were planned to make the test results relevant to military hardware.

Phase 1: Creating a Cleanliness Benchmark The first step was to establish a frame of

reference for evaluating alternative cleaners intended to replace CFC-I 13. These tests were performed at two military laboratories: The Electronic Manufacturing Productivity Facility (EMPF) - then located in Ridgecrest, CA; later moved to Indianapolis, IN - and the Naval Avionics Center (NAC) in Indianapolis.

Assembly cleanliness was evaluated through four procedures:

Ionic testing using a Resistivity of Solvent Extract (ROSE) test. Residual rosin using U.V. Spectrophotometry. Surface Insulation Resistance (SIR). Quantification/characterization of residual

~

22 February, 1994

either as little as adjusting the operat- ing parameters on Some equipment or as much as having parts suppliers mod- ify their manufacturing procedures.

erations involved.

land, VA) and AlphaMetats (Jersey City, NJl over at Ford Electronics, Markham, and a for their input in the preparation of this article. process engineer for Ford and IBM. Having

presented papers on CFC-fkee cleaning in a *Out the Author number of international conferences, he cur-

Jonathan Linton was lead engineer and rently is with Environmental Design (Toronto, p h t liaison for the no-clean process change- Canada), a consulting engineering prm. the various

The key to making a successful tran- sition from clean to no-clean technolo- gies is to consider the effect on the entire line early in the project.

Acknowledgements The author wishes to thank Dan Stewart of

Garrett Canada, along with Seho USA (Ash-

Attend the Uectronb Ciainning Pmntation Jonathan Llnton presents Session #431, Using Qualily Methods Successfully in Clean- irv Pm%@s, and SeSsMn #531, The No-Clean Opbon in E&hies Circuit Assem- W, at the UPCOminO Preciston Cleaning '94 conference (May 16-18, Rosemont, IL). See pages 30-31 in this issue for details about the event and a postage-paid inquiry form for addibonal information.

COMPLIANCE SYSTEMS, INC. assists industry in implementing environmental strategies and process improvement plans, dictated by stringent water quality requirements. We have systems varying in size, application and sophistication that are installed and serviced by COMPLIANCE at such companies as IBM. 3M. United Technologies, GE and M/A-COM

Specifically, the system featured here is designed to recirculate rinse waters in an aqueous or semi-aqueous cleaning environment, on a closed-loop basis Rather than sending these

waters to drain they are returned to the process at a specified water quality (1 -1 8 3 megohm) Our equipment can be incorporated into any manufacturers cleaning bench design We take pride in providing the highest quality service to our clients regardless of their geographical location or size Whether for analytical testing. system design and installation or service and maintenance. our clients expect and receive the best Typical Aqueous or Semi-Aqueous

I Closed-LooD DI Rinse Recirculation Svstem

For Information Circle No. 11

February, 1994 21

organics by High Performance Liquid Chro- matography (HPLC).

Results presented to the IPC meeting in Orlando, FL on April 27, 1989, included 2500 surface insulation resistance trajectories, 100 ionics readings and 100 residual rosin data points.

Test Monitoring and Validation Team (TMVT) Volunteer members of the Ad Hoc Solvents

Working Group were recruited to approve and monitor each operation of assembly and test- ing during both the benchmark and subse- quent testing phases.

Members from five groups are generally included on the teams, including commercial users, military users, the Department of Defense, and material and equipment suppliers. Dr. Leslie Guth of AT&T chairs the committee.

Although any facility with the expertise and capability can perform Phase 2 testing, most of the testing of alternative cleaners has been accomplished at the EMPF.

Phase 2: Testing Alternative Cleaners The challenge is to put all cleaners through

exactly the same process used in the Phase 1 CFC-113 benchmark tests, which included specific parameters for assembly, soldering, cleaning and testing. The Phase 2 variable is, of course, the cleaning process.

Sponsors provide the TMVT with details for their cleaning agents and also are responsi- ble for arranging their own test sites, though most choose the EMPF.

A typical test run, such as that for Inter- national Specialty Products’ Micropure CDF April 29-30, 1992, required the following ef- forts, time sequences and TMVT committee participation: 1. Preliminary testing - one to three weeks,

involving four people. 2. Assembly of Test Monitoring and Valida-

tion Team - two weeks. 3. Two days of testing - five EMPF staffers

and three to eight TMVT members. 4. SIR testing - two people, seven days. 5. Report writing - one person, three days. 6. Preparation of final document, adding com-

ments, editing, conference call - one person, oiie day. At year-end 1993, 19 alternative cleaners

had been tested and approved, but three are no longer marketed for other reasons. The 16 include:

One hydrochlorofluorocarbon (HCFC) solvent: Genesolv 2004 from Allied Chemical 12 semi-aqueous solvents: Actrel ED11 and Actrel ES from Exxon Axarel 38 from DuPont Axarel 32 from DuPont Biocat EC7 from Petroferm Biocat EC7R from Petroferm

Bioact EC-Ultra frorn Petroferm (approval

lonox MC from Kyzen KNI-2000 from Envirosolv Marclean R from Martin Marietta (for inter-

Micropure CDF from International Specialty

Prozone from British Petroleum Zestron FA from Dr. O.K. Wack Chemie GmbH Three aqueous solvents:

Armakleen E-2001 from Church & Dwight RADS from Hughes Aircraft Saponifier 2110 from Alpha

One Submitter’s Assessment The author found both positive and nega-

tive aspects to the submission of a new alternative circuit board cleaner to the Phase 2 program.

On the positive side, it is an extremely well-disciplined and fair process. We had ab- solute confidence that those that preceded us, and those following us, would be judged by the same standards. The tests are highly so- phisticated. Also, once started, the process maintains strict scheduling.

The TMVT keeps careful control over test results and how they are used in promotional materials. News releases must contain the Phase 2 sign-off sheet which describes the cleanliness test results as either “better than,” “as good as,” or “worse than” the Phase 1 benchmark. Commercial exploitation of test results is not allowed.

On the negative side, the program is costly. Tests at EMPF cost $50,000, which may put small firms with good ideas at a disadvan- tage. The other negative is that it sometimes takes many weeks to get on the test sched- ule, due to the challenge of assembling TMVT personnel for the two-day on-site test.

We learned that the TMVT and the EMPF staff worked overtime to complete our reports so we could exhibit the material at a trade show six weeks after the tests ended.

pending)

nal use only)

Products

Applicable to Other Industries? Other industries, such as precision instru-

ment bearing manufacturers, could adopt a similar procedure, if properly funded. The cii- cuit board program had the benefit of:

A relatively standard contamination to con- tend with (rosin flux). A committed core group already organized. Constant encouragement from the EPAs Dr. Stephen Andersen, who helped the group maintain its focus on the objectives. IPC’s membership commitment, interna- tional consensus and program administration.

About the Author B/anca Thayer is market specialist for lnternational

Specialty Products (Wayne, NJ).

Under observation of a Test Monitor- ing and Validation Team member of the Naval Avionics Center, a technician evaluates ionic residue, one of two key tests to determine circuit board cleanliness.

Members of the Test Monitoring and Validation Team donate their services to the test program. Observing results are, left to right: Frank Cala of Church & Dwight; 8. Carroll Smiley of DuPont; Tom Barrett of Alliant TechSystems; Rex Breunsbach of ECD; Mike Hook of the Naval Air Warfare Center: Douglas Pauls, vice