ee271.16.lecture11.test

ee271.16.lecture11.test - Lecture 12 Testing and Design for...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
SM 1 EE271 Lecture 12 Testing and Design for Testability Subhasish Mitra Stanford University [email protected] Copyright © 2016 by Subhasish Mitra
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SM 2 EE271 Overview Introduction The fabrication process is one of the most precise manufacturing methods we know of, but it it still not perfect. Each time a chip is made, there is a finite chance that at least one of the millions of transistors or wires will have an error in it. Since users of the chips assume that the chip is function, we need to have some method to sort out the function chips from the bad ones. This process is called production test, and is a critical part of manufacturing. Given the complexity of today’s chips, designers need to add features to the chip to make production testing possible. These features are called design for test.
Image of page 2
SM 3 EE271 Manufacturing Process Isn’t Perfect Source: [Spirakis ETW 2002] Void under anchor Silicon damage Metal2 extrusion/ ILD2 crack Metal 1 Shelving M4 Void Formations M4-M4 Short Poly stringer
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SM 4 EE271 Classification of Actual Defects Combinational Sequence  dependent Circuit I I 2  I 3  I I 5  I 6 O O 2  O 3  O O 5  O 6 Defect free Defective X X I I 2  I 3  I I 5  I 6 O O 2  O 3  O O 5  O 6 Circuit X X I I 5  I 4  I I 2  I 1 O O 5  O 4  O O 2  O 1 Circuit I I 5  I 4  I I 2  I 1 O O 5  O 4  O O 2  O 1 X X Circuit Timing  dependent I 1    I 2   I 3   I 4    I  I 6 O 1   O 2   O 3  O 4   O 5   O 6 Circuit Courtesy: Prof. E.J. McCluskey X Circuit I I 2  I 3  I I 5  I 6 O O 2  O 3  O O 5  O 6
Image of page 4
SM 5 EE271 Production Test Yield: Test Manufacturing process Fraction of good parts Shipped Parts Quality: Defective parts Per Million (DPM) Components, Raw Materials 10%-95% Commercial: 50-500 DPM Automotive: < 5 DPM Manufactured Parts Discarded Parts Pass? Fail?
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SM 6 EE271 Why We Need Testing? Suppose you have 99% yield – this is a very high number 1% defective parts With no testing Defect Level = 10K DPM Unacceptable !! How to measure DPM? System test: Chip operated in actual system e.g., operating system booted on a microprocessor Expensive (and not very thorough) Often used as monitor to find DPM excursions
Image of page 6
SM 7 EE271 What is Production Test? Apply input test patterns What kinds of test patterns? – will be discussed later Observe response Match observed response with correct (expected) response Assumption: Logic simulation produces expected response Test conditions (knobs) Temperature Voltage Speed
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SM 8 EE271 Automatic Test Equipment (ATE)
Image of page 8
SM 9 EE271 Cost of Test [Gelsinger, IEEE Design & Test, Jan. 2000] ITRS roadmap ~ 2015 Cents Year Test Cost per Transistor Manufacturing Cost per Transistor
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SM 10 EE271 What Does this Mean for Design?
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern