NON-DESTRUCTIVE STRENGTH DIAGNOSTICS OF NON-DETACHABLE STRUCTURES IN ELECTRONIC PACKAGES

Abstract

The represented paper is aimed at development of methods for non-destructive diagnostics of non-detachable structures in electronic packages, in particular, their soldered and welded joints, as much as such joints are considered to be the weakest link in the structure and providing their strength is an actual research task. Methods for non-destructive diagnostics of strength and air-tightness are based on acoustic-emission and electrotensometric measurement methods under the action of mechanical, thermal and pneumatic impacts. Strength testing solder joints of through-hole and surface mounted two-pin electronic components under critical stress and strain conditions  produced by simple types of mechanical forces on pull out and tension tests and pure bending tests that produce stress and strain conditions identical to operational and conducted in cyclic pulsating mode with simultaneous recording mechanical characteristics and acoustic-emission parameters showed the decrease in solder joints strength caused by their defects and provided using using acoustic emission parameters as diagnostic indicators to detect these defects and assess the strength of solder joints. The strength diagnostics for non-detachable sealing joints used to seal super-high frequency air-tight packages made from AMG-2 alloy of two types of sealing unit design representing both welded and soldered joints has been conducted by internal overpressure and temperature impacts. The stress and strain analysis of air-tight cases in conditions of pneumatic impacts has revealed that the stress in the cases is under the acceptable limit but in the joints reaches even the ultimate strength. The method for non-destructive acoustic-emission strength diagnostics as applied to non-detachable joints in electronic packages, in particular, their soldered and welded joints, has gained its progression.