EXHIBIT 8.1 Subsidiaries of ST Assembly Test Services Ltd ST Assembly Test Services, Inc. Jurisdiction of Incorporation: Delaware, United States FastRamp Test Services, Inc. Jurisdiction of Incorporation: Delaware, United States San Diego Test Equipment LLC Jurisdiction of Incorporation: Delaware, United States Winstek Semiconductor Corporation Jurisdiction of Incorporation: Taiwan, R.O.C. STATS Holdings Ltd Jurisdiction of Incorporation: British Virgin Islands