There are a lot of surface shape measurement methods. Appropriate method is selected from them in consideration of measurement accuracy, range, speed, etc. We have recently developed a system using a method among them called “linear scanning confocal surface shape measurement system”  for measuring micro objects. In this paper, we describe the method to measure the horizontal dimensions of micro objects concurrently with the measurement of the vertical dimension using this system. Generally, it is difficult to get the focused image for the horizontal dimensional measurement of micro objects because of insufficient depth of field of the optics. However, as the system has plural images at multiple Z positions for vertical dimension measurement, we thought that the focus problem could be solved by calculating the focused image from these images. As a concrete example of micro objects, microelectrodes of semiconductor products  are realistic. Microelectrodes are called bumps and electrically connects the integrated circuit chip and the package substrate. For guaranteeing the reliability of electrical connection, dimensional measurements of the bumps are required. Currently, as the density of integrated circuits increases, the arrangement density of bumps also increases. Therefore precise dimensional measurement of bumps is becoming important more and more. By using the bumps as the object under test and measuring its diameter, position and height, we confirmed the performance of developed dimensional measurement method on the system. The results showed that the system could measure a lot of bumps within a second with an accuracy of 1μm or less.
A grating projection method using a stereomicroscope is developed to provide a surface profile measurement. The phase shifting technique is applied for high accuracy detection of the projected fringe. To overcome 2(pi) phase jump caused by large step in height and to detect absolute height from the fringe number, contrast detection of the projected pattern is available. The contrast varies in relation with the distance between the sample and the objective lens. This variation is almost as same as optical sectioning that is usually used in confocal microscopy. The fast reconstruction procedure is proposed to analyze the focal point from a few images. This method is demonstrated and conformed to measure the steep surface profile of a test sample.
This paper describes a high-speed 3D shape measurement system for in-line semiconductor package inspections. The system consists of three parts. One is an optics and sensor for confocal imaging, which we call a non-scanning multiple- beam confocal microscope. The microscope can get a confocal image within very short time because XY-scanning, which is required in conventional confocal microscopes, is not needed. Another is the algorithm that performs reconstructing the object surfaces accurately from a few confocal images. The last is a mechanism that performs shifting the focused plane of the microscope very quickly. This experimental system can measure objects having a space of 9.6 X 9.6 X 0.64 mm in less than 0.4 s with an accuracy in the order of 1 micrometers .