Compact and simple ESPI devices for testing of materials and components in microelectronic manufacturing

摘要

Abstract: With the increasing packaging density of electronic components in the integrated circuits (IC) as well as on the printed circuit boards the problems with heat dissipation also increase. Electronic speckle pattern interferometry (ESPI) is a rapidly developing optoelectronic method of nondestructive laser metrology supported with computer evaluations. It permits measurements of deformations in the micrometer and submicrometer ranges produced by an electrical signal, heating, mechanical stress or another load. Though these method seems very friendly for testing microelectronic components, composite materials, miniature devices, circuit boards, wafers etc., it has several drawbacks which prevent its application in real industrial environment: complexity, bulkiness and high costs of optical setups, difficulties in aligning of the optical elements. There are problems in working outside the laboratory especially due to high sensitivity of ESPI devices against environmental vibrations and daylight. We present several methods ESPI based on which a family of devices was built. Their unique properties permit to avoid all drawbacks mentioned above. These devices are extremely simple and compact. They are easily aligned and operated even by persons who are not skilled in optics. These devices are ideally suited for working outside the laboratory even by persons who are not skilled in optics. These devices are ideally suited for working outside the laboratory for example in a well-lit industrial environment. The innovative devices permit to measure deformations both in the plane of the object surface and perpendicular to it. A detailed description of the methods and devices given. Multiple examples of ESPI computer evaluations obtained in the novel devices with different small objects under test are presented. However these devices permit to work with much bigger objects if required. Our methods and devices are also suited for qualitative as well as quantitative analysis. !16