Since the introduction of the Haswell line of CPUs, the Internet has been aflame with how hot the CPUs run. Speculation ran rampant on the cause with theories abounding about the lesser surface area and inferior thermal interface material (TIM) in between the CPU die surface and the underside of the CPU heat spreader. It was later confirmed that Intel had changed the TIM interfacing the CPU die surface to the heat spreader with Haswell, leading to the hotter than expected CPU temperatures. This increase in temperature led to inconsistent core-to-core temperatures as well as vastly inferior overclockability of the Haswell K-series chips over previous generations.
A few of the more adventurous enthusiasts took it upon themselves to use inventive ways to address the heat concerns surrounding the Haswell by delidding the processor. The delidding procedure involves physically removing the heat spreader from the CPU, exposing the CPU die. Some individuals choose to clean the existing TIM from the core die and heat spreader underside, applying superior TIM such as metal or diamond-infused paste or even the Coollaboratory Liquid Ultra metal material and fixing the heat spreader back in place. Others choose a more radical solution, removing the heat spreader from the equation entirely for direct cooling of the naked CPU die. This type of cooling method requires use of a die support plate, such as the MSI Die Guard included with the MSI Z97 XPower motherboard.
Whichever outcome you choose, you must first remove the heat spreader from the CPU's PCB. The heat spreader itself is fixed in place with black RTV-type material ensuring a secure and air-tight seal, protecting the fragile die from outside contaminants and influences. Removal can be done in multiple ways with two of the most popular being the razor blade method and the vise method. With both methods, you are attempting to separate the CPU PCB from the heat spreader without damaging the CPU die or components on the top or bottom sides of the CPU PCB.