28-06-2010, 11:41 PM
Design For Testability
Abstract
IC manufacturing process is inherently very defective. Only about 20 percent of manufactured ICs are good. But there is requirement for high quality ICs. Being able to design a workable system solution for a given problem is only half the battle .We must also be able to test the system to a degree which ensures that we can have a high confidence level that it is fully functional. The purpose of manufacturing tests is to validate that the product hardware contains no defects that could adversely affect the productâ„¢s correct functioning. The defects are converted to fault models and appropriate patterns are used to detect faults. Design for Testability or DFT is a name for design techniques that add certain testability features to a microelectronic hardware product design. The premise of the added features is that they make it easier to develop and apply manufacturing tests for the designed hardware. The purpose of manufacturing tests is to make ATPG easier. There are different types of DFT known as Ad-Hoc and Structural. Structural DFT is further classified as Scan Methods and Built in Self test. Different methods are applied according to the need and type of design. The DFT techniques applied in digital circuits are discussed. They have an effect on the cost and security of the manufactured ICs. Different test tools are being developed to make testing an easier process. DFT techniques have become an integral part of IC design due to miniaturization and ever increasing number of gates in a chip.
Abstract
IC manufacturing process is inherently very defective. Only about 20 percent of manufactured ICs are good. But there is requirement for high quality ICs. Being able to design a workable system solution for a given problem is only half the battle .We must also be able to test the system to a degree which ensures that we can have a high confidence level that it is fully functional. The purpose of manufacturing tests is to validate that the product hardware contains no defects that could adversely affect the productâ„¢s correct functioning. The defects are converted to fault models and appropriate patterns are used to detect faults. Design for Testability or DFT is a name for design techniques that add certain testability features to a microelectronic hardware product design. The premise of the added features is that they make it easier to develop and apply manufacturing tests for the designed hardware. The purpose of manufacturing tests is to make ATPG easier. There are different types of DFT known as Ad-Hoc and Structural. Structural DFT is further classified as Scan Methods and Built in Self test. Different methods are applied according to the need and type of design. The DFT techniques applied in digital circuits are discussed. They have an effect on the cost and security of the manufactured ICs. Different test tools are being developed to make testing an easier process. DFT techniques have become an integral part of IC design due to miniaturization and ever increasing number of gates in a chip.