Microcomputer Unit - Index of

QUALITYASSURANCE1. VIEWS ON QUALITY AND RELIABILITYBasic views on quality at Hitachi are to meet theindividual uers' required quality level and maintain ageneral quality level equal to or above that of thegeneral market. The quality required by the user maybe specified by contract. or may be indefinite. In eithercase. efforts are made to assure reliable performancein actual operating circumstances. Quality controlduring the manufacturing process. and quality awarenessfrom design through production lead to productquality and customer satisfaction. Our quality assurancetechnique consists basically of the followingsteps:(1) Build in reliability at the design stage of newproduct development.(2) Build in quality at all steps in the manufacturingprocess.(3) Execute stringent inspection and reliability confirmationof final products.(4) Enhance quality levels through field data feedback.(5) Cooperate with research laboratories for higherquality and reliability.With the views and methods mentioned above.utmost efforts are made to meet users' requirements.2. RELIABILITY DESIGN OFSEMICONDUCTOR DEVICES2.1 Reliability TargetsThe reliability target is an important factor in sales.manufacturing, performance, and price. It is not adequateto set a reliability target based on a single set ofcommon test conditions. The reliability target is setbased on many factors:(1) End use of semiconductor device.(2) End use of equipment in which device is used.(3) Device manufacturing process.(4) End user manufacturing techniques.(5) Quality control and screening test methods.(6) Reliability target of system.2.2 Reliability DesignThe following steps are taken to meet the reliabilitytargets:(1) Design StandardizationAs for design rules, critical items pertaining toquality and reliability are always studied at circuitdesign. device design, layout design. etc. Therefore.as long as standardized processing andmaterials are used the reliability risk is extremelysmall even in the case of new developmentdevices. with the exception of special requirementsimposed by functional needs.(2) Device DesignIt is important for the device design to considertotal balance of process, structure. circuit. andlayout design. especially in the case where newprocesses and/or new materials are employed.Rigorous technical studies are conducted prior todevice development.(3) Reliability Evaluation by Functional TestFunctional Testing is a useful method for designand prOCess reliability evaluation of Ie's and LSIdevices which have complicated functions.The objectives of Functional Test are:• Determining the fundamental failure mode.• Analysis of relation between failure mode andmanufacturing process.• Analysis of failure mechanism.• Establishment of QC points in manufacturingprocess.2.3 Design ReviewDesign Review is an orga nized method to confirm thata design satisfies the performance required andmeets design specifications. In addition, design reviewhelps to insure quality and reliability of the finishedproducts. At Hitachi, design review is performed fromthe planning stage to production for new products.and also for design changes on existing products.Items discussed and considered at design review are:(1) Description of the products based on designdocuments.(2) From the standpoint of each participant. design~ documents are studied. and for points needingclarificatio~. further investigation will be carriedout. \(3) Specify quaiity control and test methods based ondesign documents and drawings.(4) Check process and ability of manufacturing line toachieve design goal.(5) Preparation for production.(6) Planning and execution of sub-programs fordesign changes proposed by individual specialists.$ HITACHI 25