• return to the IC Fab Lab Manual Table of Contents .
• return to the IC Fab Lab Manual section on safety .

Section IV. Material Safety Data Sheets and Related Information

MSDSs on-line.

UT Austin MSDSs on-line

This information is provided to help you evaluate the relative hazards involved in handling and working with many of the common chemicals used in the semiconductor fabrication process. As you leave the university and enter the work place you will find the most common way in which such information is disseminated is via the Materials Safety Data Sheet, also known as a MSDS. You should be especially careful to look at any sections containing hazard data, such as health hazards and fire and explosion hazards, as well as sections concerning safe handling and disposal.

As an example, look at the MSDS for automotive gasoline shown on the next two pages (pp. VI-2 and VI-3 of the hard-copy version of our lab manual; here is a web-based MSDS on unleaded gasoline). Note in Section II the column labeled "Hazard Data": here you will find the statement

"8-hr TWA 300 ppm or 900 mg/m3"

The abbreviations used refer to the TLV:

Threshold Limit Value, the term used by the American Conference of Governmental Industrial Hygienists Inc. (ACGIH), to express airborne concentration of a material to which nearly all persons can be exposed day after day without adverse effects.

In conjunction with the TLV, several sub-definitions are used:

TWA: time-weighted average concentration for a normal 8-hour workday or 40-hour week.

STEL: short-term exposure limit, the maximum concentration for continuous short exposure.

TLV-C: Ceiling exposure limit, the concentration that should never be exceeded even instantaneously.

Thus the MSDS for gasoline tells us that over the course of an 8-hour work day exposure to gasoline should not exceed more than 300 parts per million (ppm). Also note this same information, with details on specific health hazards, is given on p. VI-3 in Section VI: Health Hazard Information.

Further abbreviations are defined on pp. IV-4 & 5 of the Lab Manual hard copy.

When followed properly, the laboratory procedures described in this manual, along with established laboratory practices outlined in class, should keep exposure to the chemicals we use to levels less than the TLV's given in the MSD Sheets.

• Terms used in MSDSs
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• MSDSs on-line:
  • The Vermont SIRI MSDS collection (very nice!)
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Chemicals sometimes used in our IC Fab Lab and links to their MSDSs:

• acetone .
• ethanol .
• positive photoresist:
  • representative material: HOECHST CELANESE -- AZ 5214-E PHOTORESIST .
  • representative material: HOECHST CELANESE -- AZ 1350J-SF PHOTORESIST .
• HMDS adhesion promoter: hexamethyldisilazane
  • representative material: AMERICAN HOECHST -- AZ ADHESION PROMOTER .
• positive photoresist developers:
  • representative material: HOECHST CELANESE -- AZ 422 MIF DEVELOPER .
  • representative material: HOECHST CELANESE -- AZ DEVELOPER .
• buffered oxide etch (BHF); consists of:
  • 10% hydrofluoric (HF) acid (link to MSDS for 20% HF) .
  • 30% ammonium fluoride (link to MSDS for 36% ammonium fluoride) .
• aluminum etchant; consists of approximately 60% phosphoric acid, 2% nitric acid, 2% acetic acid, balance water
  • representative aluminum etchant .
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Other web sites with useful lab safety information:

• Helpful WWW Sites.
• UT Austin Office of Environmental Health and Safety .
  • Univ. of Texas-Austin Lab Safety Manual .
  • Univ. of Texas-Austin section on MSDSs .
• Where to find MSDS on the Internet .
• The NFPA Fire Diamond .
• OSHA .
• U Virginia Health and Safety Home Page .
• Environment, Health Safety Home Page .
• MIT Safety Office .
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