SUBSTRATE SUPPORT SYSTEM FOR REDUCED AUTODOPING AND BACKSIDE DEPOSITION

摘要

A substrate support system (140, 200, 300) comprises a relatively thin circular substrate holder (100) having a plurality of passages (116, 118, 120, 240, 340) extending between top and bottom surfaces thereof. The substrate holder (100) includes a single substrate support ledge or a plurality of substrate support spacer vanes (124) configured to support a peripheral portion of the substrate backside (154) so that a thin gap (152) is formed between the substrate (16) and the substrate holder (100). The vanes (124) can be angled to resist backside deposition of reactant gases as the substrate holder (100) is rotated. A hollow support member (22, 204, 304) provides support to an underside (106) of the substrate holder (100). The hollow support member (22, 204, 304) is configured to convey gas (e.g., inert gas or cleaning gas) upward into one or more of the passages (116, 240) of the substrate holder (100). The upwardly conveyed gas flows into the gap (152) between the substrate (16) and the substrate holder (100). Depending upon the embodiment of the invention, the gas in the gap (152) can then flow either outward and upward around the substrate edge (17), or downward through passages (118, 120, 340) of the substrate holder (100), if any, that do not lead back into the hollow support member (22, 204, 304). The gas that flows outward and upward around the substrate edge (17) inhibits backside deposition of reactant gases above the substrate (16). The gas that flows downward through the passages (118, 120, 340) that do not lead back to the support member (22, 204, 304) advantageously inhibits autodoping by sweeping out-diffused dopant atoms away from the substrate front side (155). In one embodiment, the support member comprises a hollow multi-armed support spider (22) that conveys gas into selected ones of the passages (116). In another embodiment, the support member comprises a bowl- or cup-shaped structure (204) that conveys gas upward into all of the passages (240). In yet another embodiment, the support member comprises a bowl- or cup-shaped structure (304) that conveys gas upward into all but one or more of the passages (240).