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Method for evaluating silicon wafers using radio-wave reflection patterns

IP.com Disclosure Number: IPCOM000021717D
Publication Date: 2004-Feb-04
Document File: 3 page(s) / 47K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for evaluating silicon wafers using radio-wave reflection patterns. Benefits include improved functionality, improved performance, and improved throughput.

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Method for evaluating silicon wafers using radio-wave reflection patterns

Disclosed is a method for evaluating silicon wafers using radio-wave reflection patterns. Benefits include improved functionality, improved performance, and improved throughput.

Background

         Radio detecting and ranging, more commonly called radar, has a wide variety of uses from weather to aircraft location and tracking. A wave generator sends a burst of electromagnetic energy at a target. The time to return and the signal return location convey a great deal of information. As the frequency of wave gets smaller, the resolution of the data increases. When 3-meter waves are broadcast, small objects are difficult to pick out. When 1-micron waves are broadcast, the fan blades can be counted on jet engines from 120 miles away. For airborne uses, the only useful data is from the waves that bounce directly back towards the receiver. Any energy that is scattered away from the receiver is lost.

         Manual visual wafer inspection methods are error prone and labor intensive. Automatic visual inspection methods can miss errors that might be caught if the wafer was looked at using a nonoptical wavelength.

General description

         The disclosed method is evaluating silicon wafers using radio wave reflection patterns. In a controlled environment, such as in a fabrication plant, scattered energy can be gathered, and additional valuable data can be obtained. By subjecting a finished wafer to radar in an enclosure, the disclosed method can gather data about the wafer beyond what visual inspection can gather.

         A finished wafer is a collection of semiconductor, metal, and air bridges that make a topology unique to the design of the wafer. By using a radio frequency that is appropriate to the size of the details of the wafer, a 3-D image can be recreated.

Advantages

         The disclosed method provides advantages, including:

•         Improved functionality due to creating a 3-D image of a wafer

•         Improved performance due to increasing the data available for wafer quality analysis

•         Improved throughput due to inspecting the whole wafer rather than sections

Detailed description

         The disclosed method includes placing a wafer into a receiver grid that encompasses the wafer and all possible reflection vectors. A signal is...