Patent ID: 9222983
Filing Date: 2015-12-29
Classification: G01R,H01L

Abstract:
1. A monolithic stacked integrated circuit (IC) comprising a known-good-layer (KGL) test circuit having a scan segment in a first layer of the IC, the KGL test circuit comprising: a first test input, coupled to an input of the scan segment, to receive a first scan shift data; a first multiplexer, the first multiplexer having two data inputs, a selection input, and a data output, wherein one data input of the first multiplexer is coupled to the first test input and another data input of the first multiplexer is coupled to an output of the scan segment; a first test output, coupled to the data output of the first multiplexer, to send the first scan shift data to a second layer; a second test input, to receive a second scan shift data from the second layer; a second multiplexer, the second multiplexer having two data inputs, a selection input, and a data output, wherein one data input of the second multiplexer is coupled to the second test input and another data input of the second multiplexer is coupled to the data output of the first multiplexer; a second test output, coupled to the data output of the second multiplexer; a first control element, coupled to the selection input of the first multiplexer; and a second control element, coupled to the selection input of the second multiplexer.