3D Measurement Workflow for Packaging Development and Production Control Using High-Resolution 3D X-ray Microscope

Abstract

Existing technologies have become less effective for structural inspection and metrology for highly complex 3D semiconductor packages. It is virtually impossible to measure embedded structures of a semiconductor package without physically opening it. In this paper, we propose a new workflow to enable 3D structural measurements without physically altering or destroying a sample. Based on a high-resolution 3D X-ray tomography technique, we have developed a semi-automated metrology workflow to extract critical geometric information from intact packages. In the first case study, the test sample was a commercial DRAM package with a 4-die stack. We utilized the measurement workflow to have successfully extracted bond line thickness, solder volume and solder shape information. In the second case study, several smartphone camera modules were used to further validate this metrology workflow. The measurement was focused on two major components of the camera module: CMOS imaging sensor (CIS) package and lens optics assembly. After the samples were imaged with XRM at high resolution, a measurement workflow followed to measure Au bump height, volume, surface area, and other critical dimensions in the CIS package. In the case of lens optics measurement, lens gap, lens thickness, lens tilt and decentricity were measured from 3D tomographic images using the similar workflow. The workflow was scripted to test multiple repetitive parts for high repeatability and reproducibility.