Inspection to Become More Prominent

John Baliga, Associate Editor -- Semiconductor International, 10/1/1998

Custom Silicon Configuration Services (CS2, Zaventem, Belgium) has chosen the PROMIS manufacturing execution system (MES) software package from Promis Systems (Toronto, Ontario, Canada) for its new assembly and test foundry.

KINGPAQ Technology (Hsinchu, Taiwan), a new assembly subcontractor, placed orders with Kulicke & Soffa Industries (Willow Grove, Pa.) for 50 Model 8020 gold ball bonders and two Model 982 wafer dicing systems. They will be used to manufacture fine pitch chip scale ball grid array devices.

Intarsia Corp. (Fremont, Calif.) has selected the MESA manufacturing execution system (MES) from Camstar Systems (Campbell, Calif.) for use in its new facility. It will be used to track work in process, schedule customer orders and improve process yields.

Coors Ceramics Company, a wholly owned subsidiary of (Golden, Colo.) will move its Chattanooga Tenn., operation to one of its Colorado facilities.

John Baliga, Associate Editor

  Inspection to Become More Prominent

M ore stages of assembly and packaging processes are starting to require automated inspection. Vision systems are found all over the back end facility for things like alignment and detection of large defects, but the need for higher yields is bringing more automated inspection products into the back end.

Inspectech (Carmiel, Israel) exhibited its automated kerf inspection system, KIS 2000, for inspecting sawn wafers at Semicon West this year. The company estimates that a typical wafer saw handles ~$100 million worth of wafers per year. With just a 0.1% reject rate, this would lead to a $100,000 loss per year per wafer saw. Reducing false rejects and adding process control capabilities can reduce losses significantly.

The system detects backside cracks as well as kerf and chipping properties. The system tracks and creates plots for all inspection parameters, and it creates defect maps. All of this information can be used for SPC and run-to- run control, and it can be sent back to the fab to optimize or correct processes.

Electroglas recently acquired a company to be its inspection products division, and it is offering a line of products called QuickSilver to inspect microstructures, defects and bumps. They also provide advanced data processing capabilities. Also, Electroglas's acquisition of Knights Technology provides access to YieldManager, a yield management software suite used in many fabs.

Inspection products are not new in the back end. However, the presence of automated inspection and integrated data handling on par with those in front-end facilities is starting in earnest.

  Wafer Level Burn-in

M otorola Semiconductor Products Sector (Austin, Texas), Tokyo Electron Limited (TEL, Tokyo, Japan) and W.L. Gore (Gore, Eau Claire, Wis.) recently announced development of a new wafer level burn-in technology. The technology is the culmination of an 18-month joint effort by the three companies. Motorola and TEL are entering into a more formal joint development effort to prove the technology and deploy it in production. Motorola expects to begin using the technology in 1999.

The new approach uses TEL's wafer-prober technology in a controlled environment. The technique initially was designed to test bumped devices, but it will be extended to test devices of all types of interconnect.

The wafer is placed on a thermal chuck with an extremely flat surface. An electrical contact head is aligned to the wafer, and contact is made through a sheet of contact material. Gore supplies the contact material, GoreMate, which is critical to the process. Gore also developed a thermally matched interconnect board material, Inferno, designed to have the same coefficient of thermal expansion (CTE) as silicon. The matched CTE ensures contact integrity, considered one of the greatest challenges for the process.