Test Pads, Methods and Systems for Measuring Properties of a Wafer

Abstract

Test pads, methods, and systems for measuring properties of a wafer are provided. One test pad formed on a wafer includes a test structure configured such that one or more electrical properties of the test structure can be measured. The test pad also includes a conductive layer formed between the test structure and the wafer. The conductive layer prevents structures located under the test structure between the conductive layer and the wafer from affecting the one or more electrical properties of the test structure during measurement. One method for assessing plasma damage of a wafer includes measuring one or more electrical properties of a test structure formed on the wafer and determining an index characterizing the plasma damage of the test structure using the one or more electrical properties.

Description

PRIORITY CLAIM [0001] This application claims priority to U.S. Provisional Application No. 60 / 709,736 entitled “Test Pads, Methods, and Systems for Measuring Properties of a Wafer, and Systems and Methods for Controlling Deposition of a Charge on a Wafer for Measurement of One or More Electrical Properties of the Wafer,” filed Aug. 19, 2005, which is incorporated by reference as if fully set forth herein.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention generally relates to test pads, methods, and systems for measuring properties of a wafer. Certain embodiments relate to methods for assessing plasma damage of a wafer. Other embodiments relate to methods and systems for controlling deposition of a charge on a wafer for measurement of one or more electrical properties of the wafer. [0004] 2. Description of the Related Art [0005] The following description and examples are not admitted to be prior art by virtue of their inclusion in this section. ...

AI Technical Summary

Benefits of technology

"The patent describes various embodiments of a test pad formed on a wafer. The test pad includes a test structure that can measure various electrical properties, such as in-plane or out-of-plane dielectric constant, leakage, surface voltage, and threshold voltage. The test structure includes insulating structures and conductive structures, and a conductive layer formed between the test structure and the wafer. The test pad can be used in a non-contact or contact measurement technique. The isolated insulator pad prevents structures under the test structure from affecting the electrical properties during measurement. The test pad can also include a gate structure with a source, gate electrode, and drain, and the electrical properties can include in-plane or out-of-plane electrical properties. The neighboring structures can include other test structures or devices formed on the wafer. Overall, the test pad provides a reliable and accurate way to measure various electrical properties on a wafer."

Problems solved by technology

However, the necessity of direct physical electrical contact with the insulating film is particularly undesirable in many manufacturing situations.

Therefore, such a method may increase the probability that the process will be within process limits when product wafers are processed.

As the value of semiconductor wafers increases, and the demand for better throughput and more efficient tool usage increases, methods that utilize monitor wafers are becoming increasing undesirable.

For example, methods that include processing and measuring a monitor wafer require materials and labor to create and measure the monitor wafer thereby increasing manufacturing costs and reducing throughput.

In addition, measurements performed on monitor wafers may not accurately reflect properties of product wafers for a number of reasons.

Therefore, a process may not be accurately evaluated, monitored, and controlled using measurements performed on a monitor wafer.

These corona applications are typically relatively large scale in nature, and the industrial applications for which they are designed are also relatively insensitive to the level of corona, the species being produced, and the production of byproduct species.

This particular application of corona technology is sensitive to variations in corona deposition and contamination from corona deposition.

Corona generation in ambient conditions, however, may produce a number of undesirable byproducts.

In addition, the electric fields and high voltages may attract particulates into the vicinity of the corona source.

In a conventional corona deposition system, such byproducts and particulates may accumulate over time and may deposit onto a wafer and / or change the production of species being created.

Therefore, such byproducts and particulates may reduce the accuracy of measurements performed on a semiconductor wafer using a corona source, the accuracy of alterations made to a process using such measurements, and the yield of semiconductor manufacturing processes monitored and altered using a corona source for measurements of electrical properties.

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