Dielectric Etch
Dielectric etch faces multiple new materials and scaling challenges at the 45 nm technology node and beyond. New materials integration often requires etching multi-layer film stacks, including multi-layer photoresist and amorphous carbon hardmasks that define critical dimensions. Scaling challenges include maintaining etch profiles on increasingly higher aspect ratios for memory cell capacitor structures and contacts, as well as providing repeatable dimension control in high-volume production. Another concern for the back-end-of-line (BEOL) is etching various low-k materials without increasing the k-value of the dielectric or adversely impacting device performance. In addition to new materials and scaling challenges, device manufacturers’ desire to reduce overall cost per wafer has placed an increased emphasis on the ability to etch multiple films in the same chamber (in situ). |
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| DFC Technology Production-proven in high-volume manufacturing, Lam’s patented Dual Frequency Confined™ technology incorporates dual frequency power and physically confined plasma. The application of power at different frequencies provides enhanced process flexibility and allows different materials – such as oxide, nitride, organic low-k, and amorphous carbon hardmasks – to be etched in the same chamber. Physical confinement of the plasma to an area directly above the wafer prevents chemical interaction with the chamber walls, eliminating potential polymer build-up that could lead to defects on the wafer. Confinement also enables Lam’s proprietary in situ Waferless Autoclean™ technology to clean chamber components after each wafer has been etched. Used together, DFC and WAC™ technologies provide a consistent process environment for every wafer, preventing process drift and ensuring repeatable process results wafer-to-wafer and chamber-to-chamber. This combination allows multiple etch process steps to be carried out sequentially in a single chamber, which can reduce the number of systems required to etch complex film stacks, thereby decreasing cycle time and overall costs. |
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2300® Flex™ Dielectric Etch Product Family |
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| Lam’s 2300 Flex dielectric etch product family represents a continuous evolution of the productivity and performance benefits of DFC technology. With Exelan Flex45 products and beyond, DFC technology has been extended to a multi-frequency confined design that provides additional process tuning capability. These advances in system design meet the more demanding uniformity and profile requirements for applications at the 45 nm node and beyond for logic and the 50 nm node and beyond for memory. By providing a broad process window, the Flex family allows a single chamber design to meet the requirements of a wide range of applications through multiple technology generations. BEOL applications include oxide, low-k, and porous-low-k dual damascene etch with in situ photoresist strip and etch-stop-layer removal capability. Critical front-end-of-line (FEOL) applications include high aspect ratio contact, self-aligned contact, capacitor cell, and borderless contact etch. The systems are also used for mask-open etch, including in situ etch of amorphous carbon hardmasks. |
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