Scanning Acoustic Microscope (SAM) is mainly applied in Flip Chip packaging in two core directions: non-destructive detection of internal defects and process quality control. The specific applications are as follows:

1. Internal Defect Detection

Delamination Defect Location

Detect delamination between the chip and substrate, as well as between underfill and chip/substrate. Identify the position and scope of interface separation through ultrasonic reflection signals.

It is highly sensitive to micron-scale delamination and can detect invisible defects caused by thermal stress or improper packaging processes.

Underfill Void Analysis

Inspect bubbles, voids and uneven distribution inside the underfill, ensuring the adhesive fully covers solder bump gaps to avoid mechanical stress concentration and heat dissipation failure.

C-Scan imaging visually displays the location and area ratio of voids.

Solder Bump Welding Quality Evaluation

Identify defects such as cold solder, cracks and bridging of solder bumps to guarantee electrical connection reliability.

Combine B-Scan longitudinal section imaging to analyze the depth and propagation trend of internal cracks in solder bumps.

2. Process Optimization and Quality Control

Underfill Process Verification

Monitor the flow uniformity and curing effect of underfill, and optimize dispensing parameters to reduce void rate.

Reliability Test Support

After reliability tests such as temperature cycling and mechanical shock, compare scanning results to evaluate defect propagation, including delamination expansion and solder bump fatigue cracks.

Batch Automatic Inspection

Support rapid scanning of Flip Chip arrays, automatically mark defect locations and calculate defect density, improving production line inspection efficiency.

Technical Advantages and Core Capabilities

High-resolution imaging: Adopt 50–300 MHz high-frequency ultrasonic probes with micron-level resolution, suitable for miniaturized Flip Chip structures.

Multi-mode scanning

C-Scan: Plane distribution imaging of delaminations and voids;

B-Scan: Longitudinal depth analysis of defects;

T-Scan (Tomographic Scan): 3D reconstruction of internal structures.

Automatic analysis: The software automatically calculates defect area and coordinates, and generates quantitative inspection reports.

Summary of Application Value

With non-destructive and high-precision imaging, SAM provides core quality assurance for Flip Chip packaging:

Hidden hazard interception: Identify process defects such as delaminations and voids during packaging to prevent subsequent device failure.

Material performance optimization: Verify underfill integrity to improve heat dissipation and mechanical strength.

Process iteration acceleration: Optimize packaging parameters based on defect data feedback and shorten the R&D cycle.

As a standard inspection method for mass production of high-density packaging such as CPU and GPU chips, SAM meets stringent specifications including automotive-grade AEC-Q006 standards.