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Flip-chip bonding welded spot defect detection method

A detection method and point defect technology, which is applied in the field of flip-chip packaging, can solve the problems of detection and research of small defects in small structures

Inactive Publication Date: 2016-01-13
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, ECPT test objects are mainly large or large-area sample sizes such as aerospace, railway tracks, oil pipelines, composite materials, etc., and this technology has not been applied to the detection and research of small defects in tiny structures

Method used

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  • Flip-chip bonding welded spot defect detection method
  • Flip-chip bonding welded spot defect detection method
  • Flip-chip bonding welded spot defect detection method

Examples

Experimental program
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Embodiment

[0049] In order to illustrate the effectiveness of the present invention, experiments were conducted using specific flip-chip solder joints. For the sake of illustration, only three solder joints with a diameter of 1 mm were collected in this test, which are hollow solder joints, crack solder joints, and qualified solder joints, which are recorded as No. 1 solder joint, No. 2 solder joint and No. 3 solder joint. point, take the threshold Δ 1 = 1.0, Δ 2 =-2.0. The excitation current of the conductive coil is set to 220A, the frequency is 250kHz, the coil is placed horizontally, the lifting distance is 0mm, and the heating time and cooling time are 0.2s and 2.8s, respectively. Obtain temperature profiles for the three solder joints. image 3 is the temperature profile of the three solder joints. Such as image 3 It can be seen that the trends of the temperature curves of the three solder joints are consistent. Directly use the temperature curve of the qualified solder join...

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Abstract

The invention discloses a flip-chip bonding welded spot defect detection method comprising the steps: placing a flip chip in a scope of an internal magnetic field produced by a helmholtz coil, electrifying the helmholtz coil, heating a welding ball, adopting a thermal imager to obtain temperature images of the flip chip, acquiring a temperature curve of each welded spot according to the temperature images, and calculating difference with a temperature curve of qualified welded spots, to obtain temperature difference curves; then pre-judging conditions of all the welded spots according to the temperature difference curves; and next selecting a temperature image at a moment of finishing heating, extracting image blocks of empty welded spots and crack welded spots according to the welded spot pre-judged result, matching with corresponding image templates, and if matching is successful, the welded spots are determined to be defect welded spots, otherwise, the welded spots are qualified welded spots. Through combination of an ECPT nondestructive testing physical principle, the defects are detected and identified through the temperature difference curves and temperature image characteristics, and the method is short in detection time, simple to operate and low in requirements on the environment.

Description

technical field [0001] The invention belongs to the technical field of flip-chip packaging, and more specifically relates to a method for detecting defects of flip-chip solder joints. Background technique [0002] Defect detection and reliability evaluation of flip-chip solder joints play a vital role in IC manufacturing technology. As an important means to control product quality and ensure the safe operation of service equipment, non-destructive testing technology has been widely used in various fields. Currently, non-destructive testing techniques for flip-chip solder joints include X-ray testing and scanning acoustic microscopy (SAM) testing. X-ray inspection can distinguish intrinsic features of solder joints, but not vertical overlapping features, and the equipment is expensive. Scanning acoustic microscope inspection can qualitatively analyze solder joint defects, but it is easy to cause misjudgment due to differences between package structures. [0003] Pulsed edd...

Claims

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Application Information

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IPC IPC(8): G01N25/72
Inventor 周秀云周金龙
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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