BGA (ball grid array) coplanarity measuring system based on projection Moire principle

Abstract

The invention discloses a coplanarity measuring system based on the projection Moire principle, which comprises a cold light source (1), a collimating lens (3), CCD (charge coupled device) cameras (2, 4), an LCD (liquid crystal display) panel (5), a projection lens (6), an optical platform (7), a high-precision mobile station (8) and a computer (9), wherein the LCD panel (5) displays a strip pattern generated by the computer (9); the light emitted by the cold light source (1) is irradiated on the LCD panel (5) after passing through the collimating lens (3); the strip pattern displayed on the LCD panel (5) is projected to the surface of a reference plane or an object loaded to be measured on the high-precision mobile station (8); and two CCD cameras are symmetrically arranged at two sides of the LCD panel (5). The measuring area and the measuring precision of the coplanarity measuring system are increased, which can meet the demand of large-area, high-precision, quick and real-time measurement in current encapsulation test.

Description

technical field [0001] The invention belongs to the field of electronic packaging, and in particular relates to a coplanarity measurement system for packaged devices in electronic packaging, which is suitable for large-scale packaging such as BGA (Ball Grid Array, ball grid array packaging) and CSP (Chip Size Package, chip size packaging), etc. The coplanarity of large-scale integrated circuit packages is detected in real time. Background technique [0002] The integrated circuit (IC) industry has become the key to the development of the national economy, and IC design, manufacturing and packaging testing are the three pillars of the IC industry development. In actual production, due to the lack of on-line and off-line evaluation methods, many products fail to discover hidden dangers in the reliability of the products before they are put into the market, and even can only detect their processing quality and reliability through the use process of the device, which seriously h...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to propose a projection moiré coplanarity three-dimensional measurement system, which combines projection moiré and LCD phase shift technology, adopts an incoherent cold light source and a software-controlled LCD virtual grating to vertically project sinusoidal fringes The pattern is projected onto the surface of the object to be measured or the reference plane under the field of view of the CCD camera, and the cold light source is projected vertically onto the reference plane, which solves the problem of specular reflection and the problem that the grating cannot be adjusted, ensures the uniformity of the projection intensity of the entire light field, and provides more More moiré fringe information improves measurement accuracy

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