What is the connection technique of conductive paths and SMD materials in this circuit?

[bunalmis]

Wire bonding technique is used for the chips and connectors, but what about the others?

How are the conductive paths made in the circuit in the photo?

How are the smd resistor, capacitors and paths connected?

The conductive parts of the smd resistor and capacitors are painted with a brown object. What is this brown object?

 

[KlausST]

Hi,

Another useless huge filesize picture ... please read this: https://www.edaboard.com/threads/capacitance-measurement-comparator-ic.403669/post-1738930

Photo: I guess it's a hybrid on a ceeamics base. Some logic on it, some power switches, SMD resistors and capacitors....
Traces maybe screen printed with silver alloy, then baked. Also isolation layer for jumpers.

Brown: don't know..

Klaus

 

[barry]

looks like some solder on there. But, why are you asking?

 

[bunalmis]

I'm researching to see if I can do roughly the same.

 

[barry]

Hmmm…

 

[FvM]

As described by KlausST, thick film hybrid circuit, Al2O3 substrate, AgPd conductor ink (may optionally use Au for circuits involving Au bond wires), glass insulation, fired in protective atmosphere. Mostly uses regular reflow soldering for SMD components, in some cases conductive epoxy.

--- Updated Aug 15, 2022 ---

As far as I'm aware of, the shown circuit doesn't use SMD resistors, only printed thick film resistors, some of them laser trimmed.