Reduction of environmental impact of manufacturing processes
Although the manufacture of semiconductor products inherently requires water, energy, and a variety of raw materials and chemicals, Toshiba Semiconductor Company continuously strives to reduce the impact of its manufacturing processes upon the environment. Over the past two decades, Toshiba Semiconductor Company has set and achieved a series of successive goals for the reduction of the use of certain hazardous substances and the discharge of industrial waste. Toshiba Semiconductor Company is now embarked upon the fourth of these projects, known internally as Voluntary Plans. This page discusses the results of our efforts thus far in the manufacturing realm.
(1) Reduction of global warming effects
The CR Econology* Project aims to reduce the emission of carbon dioxide (CO2) and perfluoro compounds (PFCs).
- (*)Econology is a term combining economy, ecology and technology to express the idea of using technology to reduce both the cost of facility management and the emission of greenhouse gases.
- Reduction of CO2 emission:
- By the year 2010, Toshiba Semiconductor Company aims to reduce its normalized emission of CO2 by twenty-five percent (25%) from the baseline year 1990, based on the normalization of the baseline year and target year using price indexes determined by the Bank of Japan. Previous energy conservation measures centered around the improvement of facilities and efficiency of air conditioning. Although this resulted in some energy savings, Toshiba Semiconductor Company next determined to review the wafer process itself in order to scrutinize the usage of energy by manufacturing tools, and the supply energy (electricity, gas, water, heavy oil, kerosene, and other resources) required by the manufacturing processes (see figure below). The new production line for 300mm diameter wafers in Toshiba Semiconductor's Yokkaichi Operations facility has thus been designed to reduce energy consumption by approximately thirty percent (30%) compared with Yokkaichi's production line for 200mm wafers.
- Reduction of PFC emission:
- Toshiba Semiconductor Company aims to reduce its emission of PFCs by ten percent (10%) from the baseline year 1995. Toshiba Semiconductor Company also seeks to achieve this objective by the year 2010. Measures we hope to adopt include the use of abatement systems in our production lines and the substitution for PFC gases of other gases which are currently thought to contribute less to global warming than PFCs. This will be done in both new and existing clean rooms.
(2) Reduction of hazardous substances (Toshiba Semiconductor Company's voluntary plans)
As a direct result of its first two voluntary plans for the reduction of hazardous substances, collectively called Plan 33/50, Toshiba Semiconductor Company reduced its usage of 21 targeted hazardous substances by 90% by weight in 2000 as compared to 1988. Toshiba Semiconductor Company's third voluntary plan, Plan N30-5, was implemented between 2001 and 2005, and achieved and exceeded its goals for the reduction in usage of 46 designated hazardous substances. The fourth voluntary plan is now in progress.
Plan 33/50 (1988-2000)
Plan 33/50 encompasses Toshiba Semiconductor Company's first and second voluntary plans for the reduction of hazardous substances. This plan was initially created with reference to the U.S. Environmental Protection Agency's (EPA) voluntary pollution prevention initiative, announced in early 1991 and also called 33/50. Like the EPA's plan, the initial goals of Plan 33/50 were to reduce the total combined weight of Toshiba Semiconductor Company's usage of certain designated hazardous substances by 33% in 1992 and by 50% in 1995 from the baseline usage in 1988. The plan was named after these target values, 33% and 50%.
The substances targeted by Toshiba Semiconductor Company's Plan 33/50 included not only the seventeen high-priority chemical groups selected by the EPA, but an additional four types voluntarily selected for reduction, namely: chlorofluorocarbons (CFCs), arsenic and its compounds, hydrazine, and ethylene-based glycol ethers. A complete list of the 21 substances in Plan 33/50 can be found here.
| Group | Substance |
|---|---|
| A | Benzene |
| Toluene | |
| Xylenes | |
| Methyl ethyl ketone | |
| Methyl isobutyl ketone | |
| B | Carbon tetrachloride |
| Chloroform | |
| Methylene chloride | |
| 1.1.1-Trichloroethane | |
| Trichloroethylene | |
| Tetrachloroethylene | |
| C | Cyanides |
| Cadmium and its compounds | |
| Chromium and its compounds | |
| Lead and its compounds | |
| Mercury and its compounds | |
| Nickel and its compounds | |
| D | CFCs |
| E | Arsenic and its compounds |
| Hydrazine | |
| Ethylen based glycol ethers |
- Category A, B, C: Substances listed by USEPA in its 33/50 Program
- Category D, E: Substances voluntarily set to reduce by Semiconductor Company
After achieving and exceeding the objectives in its initial Plan 33/50 (see chart below), Toshiba Semiconductor Company determined to extend the plan by setting further goals for the reduction of the 21 targeted substances. In 1994, therefore, Toshiba Semiconductor Company created and implemented the second stage of its Plan 33/50. In this stage, Toshiba Semiconductor Company's objectives were to achieve normalized reductions of 33% by 1997 and 50% in 2000 of the weight of chemicals used per year divided by production output in yen, using 1994 as the baseline. As shown by the chart below, this normalized reduction effort also resulted in a substantial decrease in overall usage of the 21 targeted substances.
Between 1988 and 2000, Toshiba Semiconductor Company reduced its usage of the 21 targeted hazardous substances by over ninety percent (90%) by total weight. In absolute terms, this means that as a result of Plan 33/50, approximately 2300 tons (4,600,000 pounds) less of the 21 targeted chemicals were used in 2000 as compared to 1988.
- Summary of Plan 33/50:
-
- 21 hazardous substances targeted for usage reduction.
- First plan: 1988 to 1995
Goals achieved: 33% reduction in 1992 and 50% reduction in 1995 from baseline 1988 (reduction in total amount in use by weight) - Second plan: 1994 to 2000
Goals achieved: 33% reduction in 1997 and 50% reduction in 2000 from baseline 1994 (reduction in normalized rate of usage: weight of 21 chemical substances used / production output in yen) - Results: Over 90% decrease in usage by weight of targeted substances between 1988 and 2000; reduction in usage of approximately 2300 tons of chemicals between 1988 and 2000.
Reduction of hazardous substances achieved by Plan 33/50, 1988-2000.
Plan N30-5 (2001-2005)
Toshiba Semiconductor Company implemented its third voluntary plan to reduce the usage of hazardous substances, Plan N30-5, between 2001 and 2005. Plan N30-5 aimed to reduce the normalized rate (weight of chemicals used divided by production output in yen) of designated hazardous substances by thirty percent (30%) in 2005, compared to the baseline year of 2000. The plan was named after this 30% target and the five years it was anticipated to take to achieve the goal.
Toshiba Semiconductor Company's Plan N30-5 greatly expanded the hazardous substances targeted for reduction over Plan 33/50. Plan N30-5 included a base total of 46 chemical substances, which encompassed certain substances designated under Japan's PRTR1 law, the 21 substances carried over from Plan 33/50, and additional substances chosen by Toshiba Semiconductor Company. In addition, each manufacturing site of Toshiba Semiconductor Company was permitted to choose further substances to add to the list at its discretion. A complete list of the 46 substances in Plan N30-5 can be found here.
| Substance |
|---|
| zinc compounds (water-soluble) |
| ethanolamine (2-aminoethanol) |
| n-alkylbenzenesulfonic acid and its salts (alkyl C=10-14) |
| antimony and its compounds |
| polymer of 4,4'-isopropylidenediphenol and 1-chloro-2,3-epoxypropane (liquid); bisphenol A type epoxy resin (liquid) |
| ethylene glycol |
| ethylenediaminetetraacetic acid |
| xylene |
| silver and its water-soluble compounds |
| chromium and chromium(Ⅲ) compounds |
| chromium(Ⅵ) compounds |
| chloroform |
| cobalt and its compounds |
| 2-ethoxyethyl acetate; ethylene glycol monoethyl ether acetate |
| inorganic cyanide compounds (except complex salts and cyanates) |
| 2,2-dichloro-1,1,1-trifluoroethane; HCFC-123 |
| N,N-dimethylformamide |
| copper salts (water-soluble, except complex salts) |
| trichlorofluoromethane; CFC-11 |
| toluene |
| lead and its compounds |
| lead and its compounds (high temperature solder) |
| nickel (metal) |
| nickel compounds |
| arsenic and its inorganic compounds |
| hydrazine |
| pyrocatechol |
| phenol |
| hydrogen fluoride and its water-soluble salts |
| beryllium and its compounds |
| boron and its compounds |
| poly(oxyethylene) nonylphenyl ether |
| formaldehyde |
| tri-n-butyl phosphate |
| ammonia (liquid) |
| ammonia (gas) |
| methanol |
| hydrochloric acid (gas) |
| hydrochloric acid (liquid) |
| chlorine |
| sulfuric acid |
| ethyl acetate |
| methylisobutylketone |
| HFC （HFC-23：eliminate CHF3） |
| HCFC (eliminate HCFC-123) |
| methylethyl ketone |
Results: By 2005, Toshiba Semiconductor Company exceeded the goals of Plan N30-5, achieving a 37% reduction in the normalized rate (weight of chemicals used divided by production output in yen) of the 46 hazardous substances, compared to 2000. This 37 percent normalized reduction translated to 28 percent absolute reduction in usage by weight of the 46 substances.
Notes:
- This refers to Japan's Law Concerning Reporting, etc. of Releases to the Environment of Specific Chemical Substances and Promoting Improvements in Their Management (Pollutant Release and Transfer Register or "PRTR").
- Perfluoro compounds (PFCs) were not included in Plan N30-5 because these chemicals were separately targeted for reduction under an international agreement of the semiconductor industry associations in the U.S., Europe, Korea, Taiwan, and Japan. The industry associations determined to reduce PFCs 10% by 2010 for the baseline year of 1995. This PFC reduction goal is addressed by our CR Econology Project.
(3) Reduction of waste
As of 2001, Toshiba Semiconductor Company has achieved the goal of sending to landfill one percent (1%) or less of our total waste generated per year. Toshiba Semiconductor Company calculates the numerator by including both (a) waste sent directly to landfill by Toshiba Semiconductor Company and (b) of the waste sent to recycling companies by Toshiba Semiconductor Company, the amount of such waste that is routed to landfill by the recycling company. In each of the four years since this milestone (2002 through 2005), Toshiba Semiconductor Company has continued to meet this goal.
