KLA-Tencor Addresses New Process Control Needs For Sub-0.13-Micron And 300 Mm Production With Automated Wafer Backside Inspection
New backside inspection module helps customers eliminate or reduce defects accounting for yield losses in excess of 10 percent

SAN JOSE, Calif., Feb. 4, 2001 - KLA-Tencor Corp. (Nasdaq: KLAC) today unveiled the industry's first fully automated, production-worthy wafer backside inspection system, which provides integrated circuit (IC) manufacturers with a new strategy for combating yield loss in every process module in the fab. Designed specifically to address the unique process control needs for advanced design rule and 300 mm applications, the new Backside Inspection Module (BSIM) enables non-destructive inspection on the backsides of patterned production wafers with the sensitivity to detect particles as small as
50 nm. Field trials conducted by KLA-Tencor during the past year indicate that backside defects can account for as much as 10 percent of a fabà ¢Ã‚?Â?s baseline yield loss-amounting to millions of dollars annually in lost revenue. BSIM is sold as an option for KLA-Tencor's Surfscan SP1 wafer inspection tools. With more than 600 Surfscan SP1 tools in the field, KLA-Tencor leads the blanket film and bare wafer inspection market.

Wafer backside defects can have a significant impact on wafer and process uniformity, both of which are critical issues in advanced 300 mm processing. Results from KLA-Tencor's field trials, conducted with leading memory and logic fabs, indicate that the backsides of production wafers become contaminated or damaged at nearly every process step, including deposition, etch, and chemical mechanical planarization (CMP). The move to double-sided polish wafers for advanced 300 mm semiconductor applications is also creating a challenge since defects previously hidden in the wafer topography on the backside surface of single-sided polish wafers are brought to the surface when the backside is polished. These defects distort the front surface of wafers during subsequent photolithography exposure, causing yield-destroying "hot spots" of out-of-focus IC patterns. Backside defects can also migrate between processes, creating gate dielectric failures.

"In an increasingly competitive semiconductor market, the ability to yield higher and faster is an important differentiator, since it allows chip manufacturers to command premium margins for their products," stated Risto Puhakka, vice president of operations at San Jose, Calif.-based market research firm VLSI Research. "With the value of a single product wafer for today's leading-edge microprocessors exceeding $100,000, every chip on a wafer counts toward the bottom line. This is especially true at 300 mm. KLA-Tencor's wafer backside inspection system offers chipmakers an innovative new method to further realize the economic gains in moving to 300 mm."

Despite its importance, backside inspection has been underutilized since, until now, the process was time consuming and destructive to the wafer. To diagnose yield issues caused by backside defects, fab engineers would run product wafers through the suspected process tools, manually turn over the wafers with a vacuum wand, and scan them in a wafer inspection system. These inspections decrease the process tool's productivity and completely destroy the front side of the wafer. In addition, for 300 mm production, which requires full factory automation, manual handling is no longer an option. To avoid these problems, many fabs operate without backside inspection, but pay a substantial price in lost revenue due to backside yield loss.

"Automated, non-destructive wafer backside inspection must be incorporated as a routine step into every process module in order to recover these yield losses," stated Rick Wallace, executive vice president of KLA-Tencor's Wafer Inspection Group. "With so much of a chip manufacturer's investment riding on a 300 mm wafer, backside defects can no longer be tolerated. Our BSIM option enables backside inspection to be easily incorporated into a fab's defect management strategy. BSIM is the latest example of solutions that we're developing to make our customers' transition to 300 mm as profitable as possible."

KLA-Tencor's BSIM option employs edge-only wafer handling throughout the measurement process, so it is completely non-destructive to the unscanned side. Since the BSIM option is automated, chipmakers can employ it for monitoring product wafers at all critical points throughout the fab to provide rapid detection of backside defect problems as they occur, with minimal impact on process tool productivity.

The BSIM option is now available for shipping, and several units have already been installed at customer sites.

About KLA-Tencor: KLA-Tencor is the world leader in yield management and process control solutions for semiconductor manufacturing and related industries. Headquartered in San Jose, Calif., the company has sales and service offices around the world. An S&P 500 company, KLA-Tencor is traded on the Nasdaq National Market under the symbol KLAC.

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