This is a supplement to my original answer. For rigor, we have to make a distinction between the reality that travels in our apparatuses, and the mathematical description that we give it. However, the mathematical description proved to be so successful, that sometimes we place a sign of equality between them.
About what happens with a quantum object when it interacts with a macroscopic apparatus, we don't know. At present, we don't have a better tool to handle this problem than the collapse (reduction postulate of von Neumann). And we simply use it because we have to go on, to work.
Now, the wave-form for the wave-function works well in some cases, and works badly in other cases. But in most of the cases in which interference in involves, it works well.
For instance if we put on the way of the particle a beam-splitter, we believe that we get a splitting of the wave, into a reflected wave and a transmitted wave. I.e. although we speak of one particle, we believe that we get two waves. Then, if we redirect, with mirrors, the two waves to cross the path of one another, we get an interference pattern (see experiments with the Mach-Zender interferometer in Wikipedia) if in the crossing region we place a photographic plate.
However, the interference tableau doesn't appear for one single particle. We have to prepare many particles carefully, in an identical way, i.e. same type of particle, same velocity, etc.
So, interference pattern is produced by waves, while a single particle is detected on the photographic plate in a single place, as any particle.
Though, we incline to admit that before the detection on the plate, we had for each particle and particle, the two waves as I said above, and at the detection all the energy of the particle is delivered to one single molecule on the plate.
(The process of impressing the photographic plate is some more complicated but I restricted myself to a simple line. What is most important is that at the detection on the plate, the particle doesn't impart its energy to all the region covered by the interference pattern. No, the energy is delivered to a single point (e.g. a certain molecule is decomposed) ).