The present disclosure is a method for in situ monitoring of backside contamination on a semiconductor wafer (120) between processing steps which are performed in a multi-chamber tool (500). In a first form, a laser source (220) and a detector (210) are mounted on a robotic arm (110, 111), or within a semiconductor processing tool (500). The laser (220) and detector (210) move along with the robotic arm (110) as the robotic arm (110) shuffles the wafer (120) between processing carriers (610-650) and chambers (510-540). While in transit the backside of the semiconductor wafer (120) is scanned by a laser beam (221), whereby contamination is detected by a detector (210). The laser (220) and detector (210) then scan the backside of the wafer (120) while the robotic arm (110) is in transit and/or while the robotic arm (110) is stationary in the processing sequence. The absolute particle count and differential/incremental particulate counts are calculated on a chamber-by-chamber, and wafer-by-wafer basis, using a data processor (230).
RELATED APPLICATION
The present invention is related to U.S. Ser. No. 08/887,696 filed on Jul. 3, 1997, entitled "Method and Apparatus for In-Line Measuring Backside Wafer Level Contamination of a Semiconductor Wafer" by Jain, et al. (still pending), which is assigned to the current assignee hereof.
An invention is disclosed for backside particle removal during a semiconductor manufacturing process. Cleaning sites are defined on the backside of a wafer. The cleaning sites are regions of the backside of the wafer that physically contact a chuck during a semiconductor fabrication process. Once the cleaning sites are defined, the backside of the wafer is cleaned, where the cleaning is primarily directed to the cleaning sites. Typically, the contact regions can correspond to pin positions of a chuck pin array, or wafer contact areas on a vacuum chuck. A laser or a megasonic wand can be used to provide the site-specific cleaning of the wafer backside.
An apparatus for measuring contamination of a semiconductor substrate includes a chuck for loading a substrate, a position detection means for recognizing a front surface of the loaded substrate to obtain position data of a portion of the substrate to be measured, a first driving part for moving the chuck in accordance with the position data to measure a rear portion of the substrate, and a surface measurement means disposed under the chuck for selectively measuring metal contamination of the substrate at the rear portion of the substrate. In operation, the substrate is loaded onto a chuck, position data of a portion of the substrate to be measured is obtained by recognizing patterns formed on the substrate, the substrate is then moved in accordance with the position data to measure a rear portion of the substrate, and metal contamination is selectively measured at the rear portion of the substrate.
A wafer processing station includes an air gap chuck and a light emitter/collector assembly configured to gather light when scattered or reflected by contaminants on the wafer. The light emitter/collector assembly is driven by an actuator so that it passes across a backside surface of a wafer when supported within the chuck during wafer inspection. The wafer processing station may also include a cleaning module configured to clean the backside surface of the wafer when contaminants are discovered during wafer inspection. A computer system may be coupled to receive one or more signals from the light emitter/collector assembly that are indicative of contaminants on the backside surface of the wafer and to provide one or more control signals to the cleaning module in accordance therewith. The cleaning module may be used independently of the light emitter/collector assembly and vice-versa.
A system for cleaning semiconductor lithography tools provides for cycling a polished-side down semiconductor wafer through the lithography tool using conventional automated robotics for loading and unloading the wafer from a vacuum chuck of the lithography tool. The vacuum chuck may provide a continuous clamping vacuum feature and may include a vacuum ring that surround the periphery of the vacuum chuck. The chuck and vacuum ring may advantageously be formed of a high accuracy ceramic or plastic such as ZeroDur ceramic. The polished side of the semiconductor wafer includes grooves in a polished surface and which extend inwardly from a peripheral edge of the wafer, the grooves provide gaps between the wafer and chuck allowing the wafer to be released by a slow loss of vacuum-pressure through the gaps. The pristine clean polished surface of the wafer getters contaminating particles from the chuck.
A method of detecting contamination on a backside of a semiconductor wafer includes the steps of positioning the backside of the wafer in contact with a detection surface of a contaminant sensor, and detecting deformation of the detection surface of the contaminant sensor. The contaminant sensor may be incorporated into a fabrication device such as a wafer handling device, or can be utilized in the construction of a stand-alone device. An apparatus for detecting contamination on the backside of a semiconductor wafer is also disclosed.