AMD Fab 30: 2001 Top Fab

Maria A. Lester, Associate Editor -- Semiconductor International, 5/1/2001

First silicon on 200 mm wafers was achieved November 1998, and production of the Athlon processor using 0.18 µm CMOS technology began December 1999 at 1000 wsw. As of January, production was at 2500 wsw. This technology uses shallow trench isolation, high-performance transistors, cobalt silicide, tungsten local interconnect, and six layers of dual-inlaid copper interconnect, totaling 28 masking levels. As of May 2000, three process technologies have been qualified. Each individual process technology required approximately six months from first silicon wafer start to final production qualification.

Defect reduction

	1. An etch tool is being hooked up in Fab 30 cleanroom. (Source: AMD)

The company's philosophy of contamination control from its conception was "Build Clean Installation Methodology," where strict protocol guidelines were followed for all construction material and AMD personnel. All contractor and personnel were trained in a five-step Build Clean program to assure that all contaminating materials remained outside the cleanroom and restricted the generation of contaminants within the clean construction area. Particle levels were regularly monitored and maintained. The program also reviewed all materials used within the wetted air stream for suitability in the cleanroom, including static dissipation, outgassing and chemical resistance. All equipment entering the fab was wiped down and transferred through a specially designed "clean elevator."

In addition, the SMIF approach was used to control wafer-handling contamination and its yield effects. The factory uses a three-level design where the clean air enters the fab from the ceiling on the third level through 25% ULPA filtration, flows through the floor on the third level, and is returned on the second level. The first level is used for pumps and other supporting equipment.

The fab is separated into four protocol zones to prevent cross-contamination between the different areas of the fab (i.e. copper and non-copper areas). The protocol includes separate gowning, gloves, maintenance tools, and pods and cassettes. Also, a yield management system (YMS) helps identify yield effects through the analysis of in-line metrology data collected automatically through equipment interfaces on the metrology tools. The factory layout was designed to minimize the amount of personnel movement between areas of the fab. The layout follows a "workcell" concept that ensured that the operator would always have the process tools, metrology tools, and material handling equipment necessary to perform all process steps and supporting operations without having to leave the immediate work area.

	2. AMD Fab 30 in Dresden, Germany, is the first fab specifically designed for copper processing.

The yield ramping strategy for Fab 30's startup is based on yield benchmark from another AMD fab running the same products on Al technology. The primary goal was to start up 0.18 µm with >70% of the benchmark yield for the first production quarter, and rapidly improve the yield to exceed the yield of the Al fab after less than one year. The yield management approach includes defectivity reduction, parametric stability with 100% SPC for all process and electrical parameters and systematic yield limiter elimination. In fact, 70% of the benchmark yield was achieved in 2Q00 after only 1000 production wafers were processed. Overall defectivity was reduced by 10% per quarter in 2000. The microprocessor yield of Fab 30 exceeded the Al fab yield by the end of 2000, and Fab 30 is approaching the benchmark yield after less than one year of production.

Fab 30 Classroom Areas
Clean class (Fed Std 209E)	Particle size (µm)	Floor space (m2)	Floor space (ft2)
Class 1	0.1	195	2,098
Class 10	0.5	11898	128,022
Class 100	0.5	1289	13,870
Class 1000	0.5	2112	22,725
Class 10K	0.5	2559	27,535

Automation

New procedures were developed at AMD with the help of TRW (Redondo Beach, Calif.) to manage the automation capabilities of the hundreds of incoming tools. GEM, SMIF, auto-ID and mini-environment cleanliness was verified on every tool that was accepted. Every process and metrology tool except one minor test tool was delivered to AMD with fully integrated SMIF capability.

	3. Technicians work in front of the microscope in the CMP area. (Source: AMD)

An automated material handling system (AMHS) was set up using stockers and monorail controlled by a material control system (MCS). The AMHS and auto-ID system work together to ensure that the right lot is at the right place at the right time. The AMHS can integrate several wafer transfer systems (XFRs). Once the lot is at the tool, an equipment interface (EI) to the factory host prevents misprocessing. As of the beginning of the year, 90% of the tools in the factory have EI, and 80% are fully GEM-compliant. The cassette-based rf auto-ID system tracks material throughout the fab and works with the EI and SMIF equipment to prevent the wrong material from being processed on a tool. The equipment interface also downloads recipes and automatically verifies that the wafers will be processed according to the correct recipe.

Fab 30 uses 100% real-time single-wafer tracking of production and test wafers. Wafer sorters are used throughout the factory to move wafers and verify lot integrity. Every wafer move at a wafer sorter or a tool with an EI is traced by the factory systems. This approach minimized scheduled downtime for equipment qualifications by supporting streamlined qualification procedures, and also minimized storage space requirements for test wafers by compressing them into fewer cassettes/pods.

EHS

Fab 30 is a green fab featuring a "set aside" green belt around the site. The environmental factor was considered in all major decisions such as the reduced footprint compared with Austin; the use of the more energy-efficient SMIF manufacturing concept; the reduction of PFC and VOC emissions below the legally mandated limits; and the implementation of an environmentally friendly cogeneration power plant.

Emission control systems that are in place control the process effluents to levels significantly below the air-quality standards. Chemically treated acid and caustic process exhaust systems are in place. In addition, an energy-efficient rotor concentrator/thermal oxidizer system destroys VOCs. Point-of-use abatement devices were matched to the process. There are 14 waste drain systems that allow for efficient treatment, material recovery and recycling. Collection of process waste water from first and second rinse baths contributes to the water recycling effort, which is targeted at 70% at maturity.

All of Fab 30's electrical and thermal energy requirements are provided by a specially designed cogeneration plant that uses waste heat recovered from the production of electricity for heating and cooling the fab and associated process equipment. The Energy Center employs reciprocating gas engines in a cogeneration process 30% more efficient than a conventional all-electric solution.

This environmentally friendly approach achieves an overall efficiency of energy-in vs. energy-out of 70-80% (compared with 35-40% for conventional utility solutions). The higher efficiency also contributes to a 30% reduction in CO₂ emissions of >20,000 metric tons for the period Oct/98-Oct/99. The lean burn natural gas engines also produce 40% less NO_X and 99% less sulfur dioxides compared with the brown coal used to produce electricity in eastern Germany. It also reduced the waste heat rejected by 30%, minimizing the impact of industrialization on the local climate. Finally, the Energy Center used absorption-type chillers to turn waste heat into chilled water.

The facility is protected from fire by a hybrid automatic sprinkler system. An early-warning smoke detection system uses photoelectric and laser technology sampling to provide the earliest possible warning of fire within the cleanroom. An extensive system of gas monitoring and leak detection is in place to alert and control leakage of process gases and fluids. Automatic and remote shutdown controls are integral to the design of the liquid chemical distribution systems. Exhausted enclosures and secondary containment are employed in the delivery of hazardous materials to protect against releases.

SEMI S2 and CE Directive compliance were required for processing equipment. Fugitive emissions from maintenance procedures that must be performed within the fab (etch chamber cleans) are controlled with local exhaust trunks. Emergency showers and eyewash stations are conveniently located adjacent to fab-level egress doors, which lead onto the roof of the second level and to the protected stair towers.

The absence of structure beyond the exterior cleanroom walls allows for the introduction of natural light and the viewing of the tranquil German countryside, thus contributing to the fab's user-friendliness.

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