Method for identifying defects in materially integral connections

A method for identifying defects in materially integral connections which can occur in the area between a surface of a semiconductor element, a connecting layer and a surface of a substrate, in which, using a first measuring module,

• monochromatic electromagnetic radiation from an illumination source is directed in a continuously defocused manner onto the surface of the semiconductor element, and
• a pulse of electromagnetic radiation with a wavelength greater than 400 nm is directed from at least one thermal excitation source, and
• subsequently, within a time interval, using a digital camera as an optical detector, wherein the digital camera is focused on the interface between semiconductor element and connecting layer, at least three images of speckle patterns are captured at predeterminable times and are transferred to an electronic evaluation unit, wherein
• in the electronic evaluation unit, for at least one measuring position ij, a temporal and spatial domain analysis by the equations
• C
• ij
• =
• ∑
• τ
• ❘
• "\[LeftBracketingBar]"
• I
• ij
• (
• τ
• +
• 1
• )
• -
• I
• ij
• (
• τ
• )
• ❘
• "\[RightBracketingBar]"
• ⁢
• and
• C
• ij
• =
• ∑
• τ
• ❘
• "\[LeftBracketingBar]"
• I
• ij
• (
• τ
• )
• -
• I
• ij
• (
• 1
• )
• ❘
• "\[RightBracketingBar]"
• with Iij(τ) as captured intensity, τ as time, I as intensity and C as accumulation of the intensity difference between two neighboring identified speckle patterns are performed at the respective measuring position ij and
• a result obtained in this way is compared with results obtained in advance for defect-free and defective materially integral connections of a same type in order to decide whether specified quality criteria of the tested materially integral connection have been achieved or not.