Different manufacturers have different levels of outsourcing, from all processes are outsourced (100% outsourced), to all in house.
Sometimes some of the processes are outsourced because the majority of their machinery is now for smaller geometry, and the wafers only may be outsourced for some products to be made somewhere that has the larger geometry proceses.
....
Reminds me of an ASIC company whose customer in purchasing wanted to bring forward the next 6 months of production to that week, and asked "can't you just put more people on it?". At the time that would have been impossible even with stocks of wafers, as this was an avionics ASIC.
The testing procedure for this avionics ASIC was
Wafer test electronically room temperature Package good parts Package test electronically room temperature
Place large batch in oven and power all devices with clocks attached, and leave all parts running for a week at 125 deg C After a week slowly drop temperature to then test electronically at room temperature lower temperature to -55 deg C electronically test
Parts needed a second packaging process and then retest at room temperature.
All with full serial number of device and batch testing logged.
If new wafers are needed you can add 12 weeks in front of that.
Environmental chambers and testing for full temperature range is a long job and about every 12 to 18 months you have to strip down and replace ALL the internal wiring, connectors and boards.
Imagine the setups required for testing upto 120 off 100 pin devices in enviromental chambers and how many you require.
Designing the PCBs is also fun...