Microelectronic circuit test engineering laboratories with programmable logic

International Journal of Electrical Engineering Education, Oct 2004 by Grout, Ian, Walsh, Joseph

Abstract

A use for programmable logic is presented targeting microelectronic circuit test engineering education. These devices offer strengths in cost, time and flexibility in an educational environment. The rationale for this work is to support electronic hardware design, fabrication and test for mixed-signal integrated circuits typically used in mixed-technology systems.

Keywords microelectronic circuit test; programmable logic

Today, the use of the programmable logic device (PLD) is pervasive in educational and industrial applications. The ability to configure and readily modify complex digital circuits and systems provides many time and cost advantages. This paper will discuss a use for PLDs1,2 within an electronic engineering educational environment, along with the potential benefits that the use of these devices can provide to the student learning experience. Specifically, the development of laboratory experimentation based on the use of complex PLDs (CPLDs) will be discussed. Here, the Lattice Semiconductor Corporation MACH-Series CPLD3 is primarily considered. With the rapid increase in the use of electronic and computer engineering solutions within a mixed-technology (the mechatronic) environment, the need for 3rd level (university) graduates with the right mix of electronic circuit/system design, fabrication/manufacture and test skills, is even more essential than ever before. In this paper, an electronic engineering perspective is taken and the need primarily for electronic circuit/system test engineering education is discussed. The use of digital programmable logic is an integral part of this, with a Microelectronic Test Engineering Education Development Platform design and development, based on CPLD technology, introduced. The rationale for this is to allow the introduction of test engineering specific concepts and implementation issues within an undergraduate level laboratory teaching environment. This is to be seen as an integral support role within the development of complex mixed-technology systems.

The experiments provided are aimed at undergraduate (and potentially) postgraduate students, within a 3rd level teaching and learning environment, undertaking introductory modules in microelectronic circuit test engineering.4-6 In the main, digital integrated circuit (IC) test engineering concepts are introduced7,8 in taught modules with a strong practical emphasis and content. This allows for the use of the digital programmable logic devices currently available. However, the need to consider and introduce the concepts for mixed-signal IC9 test is also an integral part of the developed system. In particular, data converter (analogue to digital (AJD) and digital to analogue (D/A)) device test is supported. The rationale for this approach is considered as follows:

* Within a national economic context, microelectronic circuit test is becoming an increasingly important area of activity for the microelectronics industry based in Ireland. The move over the last few years has been away from industrial backend production test activities and more towards a front-end test strategy and development role. This is leading to the need for the development of new engineer and technologist skills that needs to be a concern of the university sector.

* Today, in many cases, the requirements placed on the test engineer within the electronics and microelectronics industries will have little resemblance to the requirements in years gone by. This in many cases is due to the substantial increase in size, functionality, and complexity of the product that is to be tested, along with the introduction of new fabrication/manufacturing processes.

* An engineer involved in both integrated circuit test development and production test activities will be required to be involved in a range of tasks that are performed from initial IC design concept through to final product delivery to the customer.

* High performance analogue, digital and increasingly mixed-signal ICs are encountered, from analogue (operational) amplifiers through data converters to complex, high-speed digital signal processors with analogue & digital I/O.

* Design, Test and Fabrication are interleaved processes, with complex interactions at various stages of a product development process. Test, once seen as an afterthought, is now a proactive activity starting at a design concept stage. The move is towards an integrated Design for Testability (DfT) approach for electronic and microelectronic circuits and systems, see Fig. 1.

* Test, above many other activities with the microelectronics field, requires a sound practical knowledge of concepts and design requirements, given practical limitations of the devices to test, the development of test methods and production software test programs, along with the limitations of the test equipment to be utilised.

The educational programmes delivered to the student are required to take into account these considerations and to migrate educational programmes towards the delivery of new course material with the right levels of quality and relevance. The purpose of this paper is to discuss the introduction of test engineering concepts aimed to support the introduction of a relevant graduate skills base. The focus of the paper is represented in Fig. 2.