dear classmates welcome to the VLSI testing course the first chapter is introduction in this chapter we will walk you through some important concept above your sarcastic we wish you enjoy this course at the beginning of this course we would like to quote a famous saying by Graham Schuster he said that testing is a skill while this may come as a surprise to some people it is a simple set good testing require innovative ideas and the street rules with good knowledge in testing we can achieve quality testing at affordable price so it's very important to learn about tests in this chapter we are going to provide a brief introduction in this introduction we will tell you what is testing and why is testing important in our next video we will describe many types of testing followed by the test quality and the testimony finally we will discuss important issues in testing and we will conclude this chapter so what is testing testing is a process of determining whether a piece of power is functionally correct or defective if it is functionally correct it passed the test typically we use the green color to indicate a pass if it is defective a fail the test we typically use the red color to indicate a fail in this course the piece of power is integrated circuit to be specific so what do we need to test our integrated circuit this is because during the manufacturing process we can have all kinds of defects falling in our icy so we need to test all the manufactures I see and make sure we only ship the good IC to our customer and we reject the defective I see so in summary testing is a decision process so after the testing there are four possible outcome for good I see that pass the test this is the true path is for defective IC fail the test then it's a true reject they are both correct decisions the problem is that when defective IC test the test we call it a test escape this is also known as under testing for good I see let's fail the test then we call your loss this is also known as overkill or over testing this case and the year laws are wrong decision so the goal of good testing is to reduce both test escape and the yoloz unfortunately this is a trade-off between test cost and the test quality when we want to have quality test we can reduce test escape but unfortunately we can also increase your loss if we want to have low-cost tests we can reduce yellows but unfortunately can also increase test escape now it's time for quiz based on our lecture above which of the following is not IC testing option ate some spicy Malaysian and your amplifier design to check if the output is correctly amplified option B apply an analogue signal to an analogue digital converter IC and check if the output is correctly digitized option C applied two numbers to an other IC and check its output number is correctly added so which one of these three option is not IC testing have you got it yes the answer is a in ic testing we are required to test a piece of highway that means we need a physical IC to test spice simulation is not testing have you got it correctly so why is testing so important there are three reasons a good testing can guarantee IC quality because we can reduce test is good furthermore a good testing cannot only guarantee the IC are functionally correct but also they are reliable the second reason is that a good testing can shorten time to market in photo type testing we can debug the problem of our silicon in production test if we can improve the efficiency of our testing we can reduce the test cost and make our test faster and finally if there is any ice either fail the test we can diagnose the problem find a root cause of the problem and improve they you so all of these three items can shorten the time to market and the third reason is that good testing helped to enhance our puppy because we can reduce our test costs and we can even fix some defective chips for example some memory chips can be fixed after testing and the third item is that a good testing can reduce our loss so all of the above reasons make testing very important this figure shows a typical stage of an IC product after IC is designed and a verified we will debug the problem if any after we clear all the problem we will manufacture a small amount of polluted chip and then would perform prototype testing after all the problem has been identified and fixed we then enter the main production phase we test millions of chip in production tests we sell the good chip to the customer and we diagnose the failing trip if there is any test escape the customer will bring back the test case for diagnosis after we diagnose the IC we find the root cause and we take picture of the defect we feedback this information back to the designer manufacturer and the test engineer all the blocks in great colors are related to tests so we can see that good testing is an important key to the success of an IC product so understanding tests is everybody's responsibility starting from the designer the designer need to implement design for testability or TFT sometimes we would also need viewing self test or piste the idea engineers will need to run automatic test pattern generator or ad BG and the full simulation to guarantee the party of test pattern in the mass production stage the manufacturer is responsible for your improvement and the somatic defect diagnosis and the test engineer is in charge of test cost reduction and test Quality Assurance the test house or test service company need to maintain a te automated test equipment and they need to analyze test data if there is any chip that fail the test the physical failure analysis will need to diagnose the root cause of a problem finally variability engineers need to burning the chip under sometimes performed as a ready life test on this figure we can see that testing is not only testing the nearest job it's everybody's responsibility so that we can work out a good testing in summary in this video we have introduced important concepts about testing testing is a decision process to make sure that we only sell good IC to our customer good testing requires to reduce test escape and the yoloz testing is an important key to the success of IC product because it can guarantee IC quality it can shorten time to market it also can enhance the profit testing is everybody's responsibility including a designer manufacturer test engineer EDA engineers and so on so it's very important for Eddy to learn about testing that's the end of this video we wish you enjoy the video thank you for watching [Music] [Music]