Wafer-level Variation Modeling for Multi-site RF IC Testing via Hierarchical Gaussian Process

Abstract

Wafer-level performance prediction has been attracting attention to reduce measurement costs without compromising test quality in production tests. Although several efficient methods have been proposed, the site-to-site variation, which is often observed in multi-site testing for radio frequency circuits, has not yet been sufficiently addressed. In this paper, we propose a wafer-level performance prediction method for multi-site testing that can consider the site-to-site variation. The proposed method is based on the Gaussian process, which is widely used for waferlevel spatial correlation modeling, improving the prediction accuracy by extending hierarchical modeling to exploit the test site information provided by test engineers. In addition, we propose an active test-site sampling method to maximize measurement cost reduction. Through experiments using industrial production test data, we demonstrate that the proposed method can reduce the estimation error to 1/19 of that obtained using a conventional method. Moreover, we demonstrate that the proposed sampling method can reduce the number of the measurements by 97% while achieving sufficient estimation accuracy.