Magnetic Head Writer Width Sigma Improvement Base On Six Sigma Process

In past20years, Hard Disk Drive capacity rapidly developpd as Moore Law, everysquare inch density increased to around900GB from less than1GB, while the price drops to6.33US$per GB from over800US$per GB. So high technology development made thewhole industry competition very cruel, only3HDD manufactures, HGST, WD&Seagate,survive amony over200companies after bankruptcy&merger. But in recent years whenglobal economy is in recession, Solid-State Disk develops very fast and HDD development isin bottleneck, the whole HDD industry situation become tougher.As1of the most important OEM and major external magnetic head manufacture in theindustry, the only way to survive, development and even become stronger for S company is toprovide high quality, low cost magnetic head products, besides leading the new generationhead technology development. Today situation is different and the competition no longer areother independent magnetic head manufactures, but HDD manufactures’ internal head productdepartments. Compared with S company, they can get more resource support from HDDcompanies, more HDD technologies support and special magnetic media suplied. Hence, tobeat internal head, only high enough quality and low enough cost heads can win the orderfrom HDD companies.In today mainstream PMR technology, magnetic head writer width still is1of the mostimportant technology parameters. Too narrow writer width can’t provide strong enoughwriting ability, while too wide writer width can’t achieve high track density for HDD. To hitwriter width target for every single head is the key to ensure head performance, productionyield and HDD capacity. That is to hit writer width target and reduce its sigma as much aspossible are the guarantee of good performance and production yield, then to fulfil highquality and low cost requirement.Writer width sigma is impacted by many factors, from upstream wafer process to backend slider lapping process, to dynamic performance test. How to find out the important factorsto do appropriate optimization to get improvement? Six Sigma theory is needed, its core logic,DMAIC, as direction and its data analysis tools and process control tools using as assistancefor writer width sigma improvement. This article will focus on writer width sigmaimprovement base on six sigma theory and then achieve the final target.