4520 Oxide

The Lam Research 4520 Oxide Etch is a cluster plasma tool configured for 200 mm wafers. The system can be converted to run either 150 mm or 200 mm wafers. The system operates with 208 V, three-phase, 60 Hz power and requires 175 A. The tool uses a bulkhead mounting configuration.^{[1][7][2][4][3]}

The Lam Research 4520 uses a parallel plate reactor with an inductive RF auto-tuning system. The system employs a low-pressure main chamber for anisotropic etching of dielectric films. The tool includes a moving gap between the upper and lower electrodes for process flexibility. The system uses a pick-and-place wafer transport system with non-wafer contact optical alignment and flat/notch orientation. Active temperature control is applied to both upper and lower electrodes. Wafer clamping uses an electrostatic chuck (ESC) with closed-loop backside helium cooling.^[1][7][3]

The system includes an enhanced Monochromator endpoint detector operating at wavelengths of 405 nm and 520 nm for automatic endpoint on exposed oxide. The RF power is supplied by a PDW 2200 watt generator with a LOFAT RF match. The gas delivery uses an orbital-welded gas box with mass flow controllers. Gas configuration includes lines for argon, nitrogen, oxygen, methane, CHF3, and SF6. The system uses HINE indexers for wafer handling.^[1][7][4]

The Lam Research 4520 is used for dielectric etch applications including contact etch, planarization, via etch, trench mask etch, and pad etch. The system is specified for etching 0.5 µm contact holes and above at aspect ratios of less than 4:1. The tool can etch thermal oxide at rates of 4500 Å/min or higher, BPSG at rates above 7500 Å/min, and TEOS at rates above 5000 Å/min with uniformity of +/- 10% across the wafer. Selectivity of BPSG or TEOS to polysilicon is greater than 15:1. Particle performance is less than 0.08 particles per square centimeter for particles greater than 0.3 µm in size.^[3]

The system uses a low polymer forming chemistry to achieve high selectivity to polysilicon. Process gases available include argon, CF4, CHF3, O2, CO, SF6, and N2. The tool is capable of processing wafers with dimensions from 150 mm up to 200 mm.^[2][3]